Service Slants

Tom Rosario

Jan 31, 2006 19:00 EST


Excessive oil consumption, smoke on acceleration. Owners of some 2004-05 GM compact and midsize cars with the 2.2L Ecotec Four (VINs D and F) may complain of excessive oil consumption accompanied by a spew of blue exhaust smoke every time the vehicle is accelerated. After careful analysis, GM engineers have narrowed the problem down to a misaligned cam cover oil baffle and/or a larger-thannormal PCV orifice in the intake manifold. Either condition can cause engine oil to be drawn into the combustion chambers, which, of course, will lead to the symptoms noted.

Start your diagnosis by removing the cam cover and turning it over so you're looking at the cylinder head side. Using the top illustration at right as a guide, check for heat stake marks in the areas indicated by the arrows. If you see no stake marks, chances are the oil baffle has shifted out of position. Replace the cam cover with an updated design (Part No. 24426069), and the cover gasket, as well (Part No. 12584084).

Next, move on to the intake manifold. Remove the manifold from the cylinder head and flip it over so you're looking at the gasket side. Using the illustration on the bottom, locate the PCV orifice. Now grab a 5/64-in. drill bit and try to insert its chuck end into the orifice. It shouldn't fit. If it does, the orifice is too large, which will cause the PCV system to suck oil in from the crankcase. Replace the intake manifold (Part No. 12587202) and the four donut gaskets (Part No. 24455112), along with new throttle body and PCV gaskets (Part Nos. 17202005 and 12575851, respectively).

Vehicles that are susceptible to the oil burning problem and can benefit from the new parts described are: 2004 Olds Aleros; 2004-05 Chevy Cavaliers, Classics & Malibus, Pontiac Grand Ams & Sunfires and Saturn L-series, IONs & VUEs; and 2005 Chevy Cobalts.

Note: Replacing the cam cover on 2005 Chevy Cobalts and Saturn IONs will also require an updated oil fill tube (Part No. 12589431).


Transaxle leaks, erratic fluid level readings. Some 2000-05 Ford cars and minivans (complete list below) equipped with AF50N, AX4N and AX4S transaxles may spring tranny fluid leaks from the dipstick tube grommet and exhibit wildly erratic fluid readings on the stick. Ford attributes the problems to an intermittently sticking rubber disk in the transaxle vent assembly. When the disk sticks closed it prevents proper venting of the transaxle. That, of course, causes internal pressure in the box to soar and the fluid level to rise way above spec. When the disk frees itself, the internal pressure drops like a rock, the leakage ceases and the fluid level on the dipstick returns to normal. Installing a new-design vent stem (Part No. YF1Z-7035AA) and rubber cap (Part No. XS4Z-7L282AA) into the transaxle case should put a permanent end to the problems.

To install the new parts, start by disconnecting the MAF sensor connector and removing the air cleaner housing. If the shift cable is situated directly over the vent, disconnect it from the pawl on the transaxle. Using locking pliers, pull up on the vent and remove it from the transaxle case using a twisting motion. If the vent won't budge, carefully pry it from the case using a flat-blade screwdriver. Now install the new vent stem, followed by the new rubber cap. Make sure the cap is in the first chamber of the vent. To complete the fix, reconnect the shift cable (if previously removed), install the air cleaner housing, reconnect the MAF sensor connector, adjust the fluid level and check for proper transaxle operation.

Vehicles that are prone to the problem and can benefit from the upgraded vent design are 2000-05 Taurus/Sables, 2000-03 Windstars and 2004-05 Freestars and Mercury Montereys.


Spark plug fouling. Some 2003-04 Sebring, Stratus and PT Cruiser models, along with Town & Country, Caravan and Voyager minivans (all with the 2.4L naturally aspirated Four), are prone to fouling their spark plugs during cold-engine warmup. Two newstyle replacement plug designs (Champion RE16MC and NGK LZTR4A-11) are now available to eliminate the problem permanently.

Before installing the new hotterrunning plugs, make sure they're gapped to .040 in. Chrysler recommends installing new ignition wires with the plugs, to prevent the secondary ignition voltage flashover that can occur when the cable boots take a thermal set to the old plugs.


4WD warning light illuminates while driving. Some 2001-02 Pathfinders with All Mode fourwheel-drive systems that were built before VIN JN8DR09Y*12W747550 may flash or intermittently turn on the 4WD warning light on the dash while being driven. One likely cause, says Nissan, is a damaged transfer case main oil pump. A new-design oil pump (Part No.31340-OW415), which includes an inner gear, outer gear and housing, is now available to address the problem.

Before ordering up the new oil pump, however, make sure there are no stored DTCs for the 4WD system. If there are, address them first. Also make sure all four tires are the same diameter. Finally, make sure the transfer case fluid temperature sensor circuit is working properly, and that the transfer case fluid isn't burnt. If everything checks out, install the revised three-piece pump with confidence.


Steering problems, DTC logged in BCM. Some 2003-04 CTS models are prone to illuminating the Service Steering System light on the driver information center and logging code C0450 (2003) or C1241 (2004) in BCM memory. Cadillac says that all these symptoms could be due to electrical faults in the variable effort steering (VES) solenoid. You'll find the solenoid on the upper part of the pinion housing of the steering rack.

To nail the diagnosis, put the car on a lift and remove the left wheel. Now remove the front air deflector retainers, then the deflector. Clean dirt and dust from the VES solenoid connector and disconnect it, then take a resistance reading on the solenoid with your multimeter. Resistance should be 5.7 to 7.2 ohms. If it is, the solenoid is good; look for other causes for the code. If resistance isn't within the range specified, swap the solenoid out with an improved version, Part No. 89047679.

To do the job, start by cleaning around the mounting boss on the steering rack to prevent junk from getting into the power steering fluid. Now remove the solenoid and install the upgraded version, torquing to 5 ft.-lbs. To complete the repair, reconnect the solenoid electrical connector, install the air deflector and wheel, lower the car and go on a long road test to make sure the warning light stays off.


MIL on or flashing, DTC C1735 stored. Some 2003-04 4Runners with the 2UZ-FE engine and height control system may illuminate or flash the MIL and store DTC C1735 in the suspension control ECU. According to Toyota, the most likely cause for the anomaly is moisture finding its way into the exhaust solenoid valve of the height control compressor.

The good news is that an improved, better-sealed solenoid valve is now available to address the problem. The bad news is that you're going to have to replace the entire compressor with an upgraded unit (Part No. 48910-60020) to gain the benefits from the new valve! After you perform the pump swap, clear the code, then make sure the height control system is operating properly.

Note: 4Runners that were built after VINs JTEBT17R940044493 or JTEBT14R148017908 should already have the upgraded parts installed. If you're unsure, remove the compressor and look at the four-digit date code printed underneath the mounting bracket. If the code is 4G01 or later, you've got the new compressor in your hands.

GM Truck

Belt chirp or squeal. Some 2004-05 Chevy Silverados and GMC Sierras with the 6.6L Duramax diesel may give off an irritating chirp or squeal from the drive belt at idle after a cold start. GM says the noise usually diminishes or goes away after warmup, and is most likely due to misalignment between the power steering pump and crankshaft pulleys.

Begin the repair by removing the belt and checking the position of the power steering pump pulley in relation to the pump shaft. The pulley's snout should be flush to die shaft, with a maximum deviation of no more than .039 in. either way. Reposition the pulley on the shaft as necessary, then reinstall the belt. If the noise goes away, you're done. If it doesn't and the vehicle was built prior to 6/04, remove the belt and replace the a/c compressor/power steering pump mounting bracket with an updated version (Part No. 97362175). Now, use a

Note that pickups built on or after 6/04 already have the updated compressor/pump mounting bracket installed at, the factory. But you're still going to have to open up the holes in the rear bracket to ensure proper pump alignment. Follow the procedure outlined above.


MIL on, DTC P0122 set. Acura reports that some of its 2002-05 RSX models (application list below) may illuminate the MIL and log DTC P0122 in PCM memory. According to the Japanese luxury carmaker, a contaminated throttle position sensor is the most likely cause of the trouble. The TPS accumulates crud and other contaminants not as a result of normal engine use, but rather through internal defects introduced during the manufacturing process. Installing a newdesign sensor/throttle body assembly (Part No. 06160-PND-A11, manual transmissions; 06160-PND-A61, automatics) and gasket (Part No. 17107-PNA-J01) should help eliminate the problem. You'll have to do an idle releam with a scanner after the parts swap is completed.

RSXs that are affected by the contamination issue and can benefit from the new-design parts include all 2002-04 models, 2005 manual transmission-equipped cars built between VINs JH4DC538.5S000001 and JH4DC538.5S009562 and 2005 automatic-equipped models built between VINs JH4DC548.5S000001 and JH4DC548.5S009761.


Intermittent hard steering. Owners of 2004-05 Sorento EX models built before 10/6/04 may complain of wildly varying degrees of assist from the electronic power steering (EPS) system during parking maneuvers or while driving. DTC C1012 may or may not set in the EPS control module when the problem occurs.

According to Kia, an intermittent signal from the vehicle speed sensor is the most likely cause of the trouble. Installing a new-design VSS (Part No. 96420 4A600) and extension harness (Part No. 91400 3E999) should put an end to the steering problem in no time. After installation, make sure you secure the extension harness with a tie strap to prevent vibration and excess movement. For reference, you'll find the VSS in the transmission housing on 2WD vehicles and in the transfer case on 4WD models.

Ford Truck

Brake noise. Some 2005 Escape, Escape Hybrid and Mercury Mariner models may produce a grinding, rubbing or thumping sound from the rear brakes. Ford service engineers say the noise is more obvious during cool or wet conditions, and usually occurs on the first few brake applications following an overnight set. Incompatibility issues between the rear pad friction material and rotors are the most likely cause of the noise. Installing new-design brake pads with revised linings (Part No. 6L8Z-2200-B) should put an end to the irritation. Ford recommends turning the rotors before installing the new pads.


Horn troubles. Owners of some 2005 Crown Victorias, Grand Marquis and Town Cars (build date prior to 5/6/05) may come into your shop one day complaining that the horn operates intermittently or that it takes a lot of oomph! on the steering wheel pad to get it to sound off.

The likely cause of both complaints, says Ford, is oxidation or corrosion accumulating on the horn contacts. Cleaning up the contacts and applying a contact enhancer should prevent further troubles. Here's how to go about the job:

Start by disconnecting the battery and waiting a few minutes until the residual voltage in the SRS module times out. Remove the air bag from the steering wheel. Using a Scotch Brite pad or equivalent spritzed with brake cleaner, lightly scrub the four copper contacts on the steering wheel until the rivets have a nice, shiny appearance. Repeat the drill on the four contact points on the back of the air bag assembly. Wipe all the contacts down with a shop rag to remove any residue.

For a contact enhancer, Ford recommends using a bottle of Motorcraft Rear Window Defroster Repair (Part No. PM-11). Lightly coat the copper rivets on the steering wheel with the liquid. Allow them to air-dry at least five minutes, then apply a minimum of two more coats. Make sure each coat is applied smoothly and that there are no lumps or globs of the liquid. To complete the repair, push the air bag wiring into the recessed cavity of the steering column, reinstall the air bag, reconnect the battery and check for proper horn operation.

GM Truck

Exhaust noise. Some 2002-05 full-size GM trucks with 4.8, 5.3 and 6.0L engines (VINs N, U, T, V and Z) may produce a loud popping or snapping sound from the exhaust at idle or immediately after engine shutdown. According to GM service engineers, the most likely cause of the noise is abnormal contact between the muffler and heat shield, due to the different expansion and contraction rates of the two dissimilar metals. Cutting off the old heat shield and installing an updated design (Part No. 15253526, 4.8 and 5.3L engines; 10393433, 6.0L engines) should help eliminate the racket. To complete the repair, you'll also need three heat shield straps (Part No. 10391259) and a new exhaust clamp (Part No. 15103174, 6.0L engine only).

The following vehicles are susceptible to the exhaust noise and can benefit from the upgraded hardware: 2002-05 Cadillac Escalades & Escalade EXTs, Chevy Avalanches, Suburbans & Tahoes and GMC Yukons, Yukon Denalis & Denali XLs; and 2003-05 Cadillac Escalade ESVs and HUMMER H2s.

Note: To prevent rattling, install the heat shield straps so the worm screws are positioned on top of the muffler. Tighten the straps, then cut off the excess material and bend the remainder over the three screw heads.

Ford Truck

Exhaust odor. Some 2003-05 Excursions, 2003-06 F-Super Duty pickups and 2004-06 ?-series vans (all with the 6.0L diesel engine) may produce an obnoxious diesel odor that permeates the passenger compartment. Leakage from one or both exhaust manifolds is the likely cause of the smell, say Ford service engineers. A new-design manifold gasket (Part No. 5C4Z-9448-A) is now available to address the issue.

As for diagnosing the problem, Ford recommends using a smoke machine to induce low-pressure smoke into the exhaust pressure tube of the big diesel (after the EP sensor is removed). After a few minutes, you should see smoke exiting around the manifolds or Y-pipe if there's a leak.


Inaccurate fuel gauge. Honda wants you to be awarethat some 2003-04 four-door Civic EX and LX models (VINs starting with 1HG or 2HG) may produce erratic or fluctuating fuel gauge readings. The chief complaint you'll probably hear is that the fuel needle will suddenly drop by about a quarter of a tank (three or four graduations) for no apparent reason. In some cases, the gauge will indicate Empty and the Low Fuel light will come on. Then, after driving for several minutes or cycling the ignition key off and back on, the gauge reading will return to normal. To make matters worse, all these symptoms are intermittent, with the gauge working fine for days at a time, then mysteriously acting up without warning!

Honda attributes all of these symptoms to software incompatibility issues between the fuel gauge and fuel level sensor. Replacing the entire instrument cluster is your only recourse. Here's a list of the vehicles affected, and the new-design clusters available to restore order:


Exhaust ping or rattle. Owners of some 2003 Outlanders (build date prior to 5/03) may complain of abnormal exhaust noise under acceleration. Among the customer comments you might hear is that the noise sounds as if there are "marbles in the exhaust" or that there's "a weird pinging noise" on acceleration.

Mitsubishi attributes the condition to the flow of exhaust gases colliding within the internal structure of the front exhaust pipe. Installing a new-design front pipe with smoother internal contouring should help alleviate the noise in short order. For FWD Outlanders, order Part No. MN180578; for AWD versions, order Part No. MN180579. The front and rear exhaust gaskets are identical for both models-Part Nos. MB687021 and MB687002, respectively.

GM Truck

Transmission slip, low power, 2nd gear start. Owners of some General Motors full-size trucks equipped with the 4L60-E or 4L65-E transmission may complain of a slipping sensation or low power when launching the vehicle and/or a 2nd gear start when accelerating from a stop. According to GM, the symptoms occur very infrequently (perhaps once every few thousand miles or so) and could be the result of erratic or intermittent signals from the vehicle speed sensor. The General doesn't recommend testing or replacing the VSS, but rather that the PCM be reprogrammed with updated software. You'll find the new ash files in TIS satellite data update version 5 or later.

If you encounter 2nd gear start complaints with the above transmissions but they occur much more frequently, here are some tips from GM powertrain engineers that should help you get them straightened out:

1. Always check for DTCs, even if the MIL isn't illuminated. Remember, certain engine driveability issues can cause a launch to occur in other than 1st gear.

2. Debris on top of the spacer plate or in the valve body, or a leaking shift solenoid, can cause a 2nd gear start, and with greater frequency than an out-of-kilter VSS. Drop the pan and take a look around, if need be.

3. Don't start off with the shift selector in D2. You'd be surprised how many drivers do this, and don't even realize it! A quick test drive with the owner behind the wheel should nail this one pronto.

Vehicles that are susceptible to the quirky transmission symptoms and can benefit from either the reprogramming job or the diagnostic tips noted above are: 2004-05 Cadillac Escalades; Chevy Avalanches, Express Vans, Silverados, Suburbans & Tahoes; CMC Savana Vans, Sierras & Yukons; and HUMMER H2s.


Extended crank. Owners of 2004 TaComa and Tundra trucks may complain about extended crank times after the engine is shut down for a few minutes and an attempt is made at restarting. Toyota attributes the condition to a rapid loss in fuel pressure that results from a defect in the fuel pump s suction tube assembly.

To confirm the diagnosis, hook up your fuel pressure gauge and start the engine. Now shut it down and check the gauge reading. If the residual pressure holds, look elsewhere for the problem. If it drops sharply, you've nailed the suction tube as the villain. A new-design tube assembly is now available to address the problem. For the midsize Tacoma, order Part No. 77203-04060 for 2RZ-FE and 3RZ-FE engines, 77203-04070 for 5VZ-FE engines. For the brawnier Tundra, go with Part No. 77203-0C050. The suction tube assembly gasket (Part No. 77169-04010) is identical for all models and engines.


Tranny slippage, erratic shifts, no 3rd or 4th gear. All 1999-2004 GM RWD cars and light trucks (including 2003-04 HUMMER H2s) with the 4L60-E or 4L65-E automatic are susceptible to transmission slippage, erratic shifting and/or a loss of 3rd or 4th gear. In addition, the MIL may be illuminated with DTC P0757 stored in computer memory. According to GM, all these problems could be the result of metal chips or debris plugging the bleed orifice of the 2-3 shift solenoid. The code could also set if the 2-3 shift or shuttle valves get stuck in their bores because of the junk. Getting rid of the debris is crucial to a successful resolution.

Start by inspecting the 2-3 shift valve, the 2-3 shuttle valve and their respective bores. If need be, clean the valves and bores with a suitable cleaner, then blow-dry everything with compressed air and reinstall the valves. Now move on to the 2-3 shift solenoid. Remove the solenoid and clean it up with the solvent. If the opening has a metal protective screen to prevent clogging, reinstall the solenoid. If it doesn't, replace the solenoid with an updated, screened version (Part No. 10478131).

Ford Truck

MIL on, DTCs set. Some 2001-03 E-and F-150s with the 4.2L V6 may illuminate the MIL and store DTC P0171 and/or P0174 (lean bank 1 and/or 2) in PCM memory. One likely cause is that the isolator bolts and port gaskets at the interface between the upper and lower intake manifolds have sprung a leak, allowing unmetered air into the intake stream. Ford says the condition can be intermittent, and may disappear when the engine is warmed up.

To check things out, hook up your scanner and start hunting for codes. If DTCs in addition to P0171 or P0174 pop up on the display, take care of them first. If all you get are the lean exhaust codes, remove the upper intake manifold and toss the old isolator bolts and gaskets. While you have the upper manifold off, check the EGR orifices that are pressed into each primary port of the lower manifold for excess carbon or soot. If you see deposits, remove them with a pick and strong solvent. To complete the repair, reinstall the upper intake manifold using new-design port gaskets and isolator bolts (Part Nos. 1L3Z-9H486-AA and 3F2Z-9S479-AA, respectively).

Note: Using winter-grade fuels in hotter-than-normal ambient temperatures can lead to vapor lock, which will cause symptoms similar to those described here. Oxygenated fuel will only compound the problem. If the MIL illumination is intermittent and nonoxygenated fuel isn't available, ask your customer to switch to a tank of high octane gasoline. This fuel has a lower volatility and may help alleviate the lean exhaust condition.


Leak-detection dye precaution. Saturn warns that using any ol" trace dye in the cooling systems of its 1996 to present cars and SUVs can lead to confusion and possible system contamination. Here's why: When in a cooling system, most common leak-detection dyes give off a greenish hue. Problem is, DEX-COOL antifreeze, which has been used by Saturn since 1996, has an orange color. If a technician sees a greenish tint in the reservoir bottle of a Saturn vehicle during routine work, he may mistakenly think that the cooling system has been flushed and filled with conventional (green) antifreeze. So he'll add more of the stuff, which will ultimately contaminate the DEX-COOL-based system.

To avoid such problems, Saturn now recommends the use of a newly formulated trace dye (Part No. 89022219). The new dye will still fluoresce brightly with a UV or blue inspection lamp, but it won't change the color of the DEX-COOL. Saturn says the dye can be used with conventional green coolants, as well.


Engine surge. Some 2001 Maxima models (complete application list below) may produce a disconcerting engine surge between 40 and 60 mph. Nissan says the problem can occur while driving on a level surface or a slight uphill grade under steady throttle or under slight, steady acceleration. A fluctuating throttle position sensor signal coupled with a drop in spark advance are the causes of the driveability concern. Oddly, Nissan recommends replacing the PCM rather than the TPS to effect a solution.

Before going the replacement PCM route, however, hook up your scanner to the DLC and get the vehicle on the road with a buddy in the drivers seat. Once the car is up to about 50 mph, make sure the throttle is held steady and wait for the surge to occur. When it does, look at the PIDs for the TPS and timing. If the TPS voltage looks steady and the spark advance timing doesn't deviate from the norm, this fix doesn't apply; look elsewhere for the problem. If the TPS voltage fluctuates wildly and the spark advance drops lock a rock to 0°, replace the PCM with an upgraded unit as follows:

Maximas that are susceptible to the surging condition and can benefit from the updated PCM include models equipped with side air bags and built between VINs JN1CA31A*1T109169 and JN1CA31A*1T311644, and models without side air bags built between VINs JN1CA31D*1T620696 and JN1CA31D*1T822582.


Intermittent no-crank. Owners of 2003 De Villes may complain of an intermittent no-crank condition. According to the General, one likely cause is a poor connection at one or more of the three electrical connectors leading to the engine wiring junction block. You'll find the junction block at the right front of the car, just behind the radiator support.

To check things out, start by disconnecting the battery ground cable and removing the junction block cover. Then remove the positive battery cable from the junction block. Next, loosen the fasteners that secure the three electrical connectors to the block. Release the locking tabs, then separate the connectors from the junction block. Now check the male and female terminals closely for corrosion, cleaning as necessary. Reconnect the electrical connectors, making sure they're fully seated in the block. Reengage the locking tabs, then tighten the fasteners to 62 in.-lbs. To complete the fix, reconnect the battery positive and ground cables, install the junction block cover, then crank the engine over repeatedly to verify that the no-crank condition has been rectified.

© 2006 Hearst Business Publishing Provided by ProQuest LLC. All Rights Reserved.

Source: Motor


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