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2007 Jeep Compass - Appears to be stuck in 4wd

16K views 11 replies 9 participants last post by  4x4GP 
#1 ·
I have a 2007 Jeep compass 4x4 Sport that I recently purchased that appears to be stuck in 4wd. I would very much appreciate anything anyone could share with me that might help me troubleshoot what I need to replace:

There are no error lights on
  • 4wd light comes on and off when the 4wd Lock lever is engaged
  • 4WD! light comes on when the ECU fuse is pulled
  • Traction control light works but is not on
  • ABS light works but is not on
  • Check engine light works but is not on

However - the vehicle definitely seems to be stuck in 4wd - I can feel it binding when turning etc. This does not change with 4wd light on or off.
  • Reversing to try to release a mechanical bind had no impact
  • There is an almost "propane" smell in the vehicle - probably dripping or burning gear oil
  • The front differential was replaced 6,000 miles before I bought it
  • The rear differential gets hot when being driven
  • There are no errors in the ODB2 record

One possible issue is that the tires are slightly mismatched (and have been since I bought it)?

I have seen others with a similar challenge posting in other places but nobody has posted a resolution that I can find. There are some issues that are somewhat similar with speed sensor issues but those seem to universally throw a Traction Control error.

I am hoping there is some way to release the ECC somehow and free the rear end?
Are there troubleshooting steps for the PTU / RDA etc?

Any help would be greatly appreciated
 
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#2 ·
Pull the ECC fuse, then you will be in FWD mode and see if that gets rid of the problem.
 
#4 ·
Honestly - no. I took it into a local Transmission and Gear shop - they felt the transmission was bad and referred me to the dealer. After they looked at it the transmission is slipping. They were not really well versed in the details of the PDU or the ECC. They told me that the dealer will have to program a transmission as part of the installation process and I cannot meaningfully get a used transmissions. Candidly I don't believe them. Worse, after they looked at it the transmission is slipping. I am certainly not going to pay a dealer for a transmission. I feel like whatever else was wrong with it - with the transmissions slipping it isn't going to be economically viable to repair.
 
#7 ·
Hey Ellie, I am a friend of Drews. Turns out his ECC was malfunctioning and replacing it solved the issue. .It can be purchased for around $300 online and as things go it was easy to replace.
1. Drain the read differential
2. Pull the driveline (4 bolts)
3. Pull the ECC (4 bolts)
4. Do the reverse of above to reinstall the ECC, don't forget to refill the differential and sealer between the ECC and the differential housing.

The ECC is a clutch that is normally disengaged and it is engaged by a small electro magnet. If you pull the ECC fuse then there is no power and it should allow the ECC to slip. We found that the binding issue occurred on Drews jeep even with the fuse pulled. There were no error codes or 4wd dash lights before we pulled the fuse. We noticed we could not make the new ECC slip by hand so we thought something must be wrong but after we installed the new ECC the jeep drove normally, no binding. I think there is normally a lot of drag on the clutch. I suspect because of the drag it seems like rear wheels are still engaged when the car is up on jacks. I suspect there is no mechanism to disengage the front wheels from the driveline. The real wheels are just controlled by the ECC and the driveline is always engaged..

Jay
 
#5 ·
I have a 2007 Jeep compass 4x4 Sport that I recently purchased that appears to be stuck in 4wd. I would very much appreciate anything anyone could share with me that might help me troubleshoot what I need to replace:

There are no error lights on
  • 4wd light comes on and off when the 4wd Lock lever is engaged
  • 4WD! light comes on when the ECU fuse is pulled
  • Traction control light works but is not on
  • ABS light works but is not on
  • Check engine light works but is not on

However - the vehicle definitely seems to be stuck in 4wd - I can feel it binding when turning etc. This does not change with 4wd light on or off.
  • Reversing to try to release a mechanical bind had no impact
  • There is an almost "propane" smell in the vehicle - probably dripping or burning gear oil
  • The front differential was replaced 6,000 miles before I bought it
  • The rear differential gets hot when being driven
  • There are no errors in the ODB2 record

One possible issue is that the tires are slightly mismatched (and have been since I bought it)?

I have seen others with a similar challenge posting in other places but nobody has posted a resolution that I can find. There are some issues that are somewhat similar with speed sensor issues but those seem to universally throw a Traction Control error.

I am hoping there is some way to release the ECC somehow and free the rear end?
Are there troubleshooting steps for the PTU / RDA etc?

Any help would be greatly appreciated
I recently bought a 2010 Compass. I have A slight front end shake. I wanted to spin the front wheels to check the tires. Traction control off, 4wd off. The rear wheels are pushing it off the jack stands. 4wd must be stuck on.
 
#9 ·
I had a similar problem with my 2008 Jeep compass . It ended up being the switch lever. It works opposite when the light is off power stays to the solenoid and keeps it engaged. I changed the switch and it works perfect sounds crazy but that was the problem. It took me forever to figure it out these things have so many electrical issues. I hope this helps someone
 
#10 · (Edited)
It could be related, to check that first:
From the repair manual, page 306.

The All Wheel Drive (AWD) Control Module controls the Electronically Controlled Coupling (ECC) mounted on the rear axle. It is located in the left kick panel area and gets signals over the vehicle bus.
 
#11 ·
I'll paste the entire page below:

The all-wheel-drive system requires no driver input or control. Under most driving conditions, it is passive and power is transmitted to the front wheels alone. Unlike all-wheel drive systems that rely on pumps or viscous fluids to transfer torque, this system requires no front-to-rear slippage for activation. This allows the system to transfer torque solely in response to accelerator pedal position. If the driver is asking for a lot of power, the system immediately starts clamping the electronically controlled coupling (ECC), transferring a high percentage of power to the rear wheels. This avoids front wheel slippage, as power to propel the car is transmitted through all four tires. This mode of operation is called open-loop operation in that there is no feedback to affect the torque transfer.

A second, closed loop, operating mode uses feedback from the wheel-speed sensors to determine the appropriate torque transfer. When the front wheels slip, the All Wheel Drive (AWD) Control Module tells the ECC to start clamping, sending power to the rear wheels. Attempting the same aggressive launch described above with the front wheels on ice and the rear wheels on dry pavement, the ECC sends even more torque to the rear wheels to minimize slippage and launch the vehicle. Both modes are always active with the closed loop mode layered on top of open loop mode to increase torque to the rear wheels when needed to maintain traction in extreme cases.

Power to the rear wheels is modulated under the following conditions:

Slipping on ice while backing up will send a lot of power to the rear axle

Loss of traction while traveling at freeway speeds, for example hydroplaning on a puddle of water, will send very little power to the rear wheels because the controller knows at those speeds a lot of power is not needed at the rear wheels

A third condition, which is independent of the others, uses wheel speed differences to determine when the vehicle is turning in a tight circle. This condition, which is indicated by a large discrepancy in side-to-side wheel speeds, causes the electronic control module to reduce torque to the rear wheels to prevent binding in the driveline. The electronic control module is always checking for this condition as well.

A fourth condition that is unique to this system is to influence vehicle dynamics. Other systems limit AWD to aiding traction or providing off-road capability. The primary focus is on launching the vehicle or going off road at speeds up to about 25 mph (40 km/hr). Above that speed range, they use it to limit wheel slip for traction. On this system, additional ECM calibration controls torque to the rear wheels for improved handling in the 25-65 mph (40-105 km/hr) range. In this speed range, the system increases torque to the rear wheels during cornering with the throttle open to make the car turn more easily - make the handling more neutral. This is more readily accomplished with an electronically controlled system, than with viscous-coupling or gerotor systems that require some degree of front-to-rear slip to transfer torque to the rear wheels. Above 70 mph (113 km/hr), the control strategy provides minimal torque to the rear wheels under normal driving conditions to aid fuel economy.

The control module also interfaces with the Electronic Stability Control (ESC) and traction control systems. The interface allows the ESC system to use the ECC to help gain control of the vehicle. For this purpose, torque transmitted to the rear wheels by the ECC can be reduced. This system is not traction control. It only works on situations where front-to-rear traction varies, for instance, front wheels on ice, rear wheels on dry pavement or climbing steep grades. AWD does not aid side-to-side traction. ESC does that through brake intervention on this system.
 
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