Jeep Grand Cherokee 2.7 CRD not revving or accelerating

[Askula]

Hi everyone,

First and foremost, I would like to thank you all for your effort in trying to help me out.

The ECU was the culprit, thus, the independent Jeep specialist were I took the Jeep, replaced the ECU with a used one and reprogrammed it, thereby, costing in total £450.

The Jeep drives fine, thus far.

Regards,

Askula

[Harlekin]

hi
i'm new here and i'm from europe austria.
i have the first time the same problems with my wj. i have check all and the final is that the ecu was broken. i have change the ecu and drive 3 days. then the same problems but i can drive. but the car have no power, like the turbo was broken but it isnt.
the MIL is on and when i delete the codes the MIL comes after 3 seconds again.
i dont drive for 1 or 2 days and check all again. then i read the codes and now are other codes. but the new codes say the same how the first. power to high or to low.
here the new codes. p836, p651, p530, p520, p235
i have realy no idea whats the problem is.
anyone here maybe???

[Clarky]

All codes relate to sensor readings not correct, as said before earlier in this tread start with the battery as Jeeps are very sensitive to low voltage or poor quality battery's. Or you have a shorted/broken wire, wiring looms can become brittle with age, check for missing insulation & exposed wires around where the wiring comes in contact with the body.

http://www.wjjeeps.com/faultcodes.htm

[Harlekin]

i have change the battery but nothing. same problems like before.
any ideas where the problem is at the cable?
some points in at the harness where it can be???
sorry for my bad english guys.

[Clarky]

I would start with the plugs/connectors into the ECU & work back, there was a thread here that talked about a faulty loom at the back of the engine so maybe there.
good luck

[fester]

Originally Posted by Harlekin

hi
i'm new here and i'm from europe austria.
i have the first time the same problems with my wj. i have check all and the final is that the ecu was broken. i have change the ecu and drive 3 days. then the same problems but i can drive. but the car have no power, like the turbo was broken but it isnt.
the MIL is on and when i delete the codes the MIL comes after 3 seconds again.
i dont drive for 1 or 2 days and check all again. then i read the codes and now are other codes. but the new codes say the same how the first. power to high or to low.
here the new codes. p836, p651, p530, p520, p235
i have realy no idea whats the problem is.
anyone here maybe???

P0235 - Boost pressure sensor
P0520 - Oil pressure sensor circuit
P0530 - A/C pressure sensor
P0651 - Sensor reference voltage B circuit
P0836 - Transfer case position sensor

These are the sensors in question so you need to check each of their wiring.

I'm not exactly sure what the "sensor reference voltage B circuit" is but in the manual it states - Set condition: The ECM detects a short to voltage on the Sensor Reference Voltage B circuit or the Accelerator Pedal Position Sensor 5 Volt Supply circuit.

Part of the trouble shooting on this states to disconnect the boost pressure, oil pressure and A/C pressure plugs for testing so I would be inclined to start with this circuit first.

Sorry I can't give the full trouble shooting info on this but I have no idea how to copy text from a PDF file. If you have a look in the Everything 2.7 sticky thread I'm pretty sure there is a link to download the manual. Suggest you have a look as it will give you some of the test procedures.

Clarky said check the loom behind the engine but I think this is for the WH V6 diesel not the 2.7.

[Clarky]

Was a WJ but the 4.7

Originally Posted by ozjeepster

Got the one at work running sweet as at idle , I completely stripped out the wiring harness & replace 4 complete wires from PCM C1 -1 sensor earth to the CAS plug - 1 sensor signal from CPS to PCM C1 plug & the complete earth sense wires on the injector circuit , they were all corroded inside the insulation for about 8 inches from the PCM & sensor plugs , I'd say from water getting pushed in past the seals in the plugs from being cleaned with a pressure wash over the years , took her for a drive and she went well except for an intermittent misfire on cylinders 8 & 6 so that's tomorrow's job , to sort that little glitch out how's yours going mate

Probably not related though.