HELP!

[honda]

2012 JEEP GRAND CHEROKEE 3.00 CRD

Engine started, loud mechanical clatter under bonnet, engine and oil warning lights came on and unable to shift out of Park, presumably as there is something wrong and system will not allow car to be driven.

Assistance called and an hour later when it arrived engine started normally, no warning lights, shifted into Drive and vehicle was driven away normally.

First driven again normally two days later and on fourth start the same thing happened and half an hour later vehicle was started normally and driven to Jeep garage.

Garage unable to reproduce fault and after full diagnostics routine (£110.00) showed no faults Jeep returned as serviceable.

Unwilling to drive again as there is obviously a fault somewhere. If it wasn’t for the clatter I would suspect a rogue sensor but something is mechanical is obviously wrong. Any ideas please?

[V]

I am not familiar with your engine so will do my best to give you some general suggestions for what to do next. Has anyone done any work on the engine or fuel tank this year? If so what? Has it been misfuelled with petrol?

 

From your description it sounds like a Crank Position Sensor or Cam Sensor type of fault but this should show up as a stored Diagnostic Trouble Code (DTC) P0336.

 

Your Jeep has a high pressure fuel injection pump (CP3) that has three pistons inside. These can clatter if they are out of phase with the injectors or there is some other fault that affects them delivering full fuel pressure which I think is something over 2500psi. From what I have read, I think the pump is driven off a camshaft so there may be a possibility that if the pump is removed, reinstallation needs to be timed/aligned correctly.

 

A 'Full Diagnostic' can mean anything but at it's worst just means someone plugged in an OBD2 scanner and checked if any DTCs were stored. Ask the garage for an itemised list of the diagnostic checks performed that were not an OBD2 scan check.

Edited September 6, 2021 by V

[honda]

Thanks, your help is much appreciated.

In response to your questions:-

 

The battery and alternator were replaced in June. (after  it seems that faulty diodes "killed" the alternator which in turn "killed" the battery. Although this was the subject of a recall in other countries notably Australia Jeep UK denied liability for the problem.) Jeep was serviced on 9th August and was scheduled for recall for a fuel pump fault but parts were not available although this has now been completed during the recent visit.

 

As suggested I will ask the garage for an itemised  list of the diagnostics checks (I was briefly shown six sheets but I didn't look at them as they appeared to be just numbers. 

 

Thanks again for your guidance.

[V]

I just found some Jeep specific info that says that the CP3 does NOT need to be synchronised. See Jeep OM642.

[V]

Your Jeep is likely to have two fuel pumps, an electric one in or near the fuel tank and the high pressure pump (CP3). Find out what work was done recently to which fuel pump. I reckon your fault could be related to that work.

[honda]

Thanks

 

The fault occurred before the work was done on the fuel pump but maybe the faulty petrol pump caused the problem in the first place although the garage say that the faulty pump could not cause the problem. The last incident occurred after the work was done.

The recall was V62 and I am trying to find out what that entailed.

[honda]

Thanks but I have no idea and will check the engine type if I can

[V]

Oops, my mistake. Your knowledge is better than mine on when they switched back to VM. Allpar says the switch was in 2011. The DTCs are likely to still be the same for Chrysler. The Fiat MultiJet II system uses a lot of Bosch parts so it's likely to have a similar technology of Bosch high pressure pump (CP4).

[honda]

Thanks, Very interesting but rather above my head! I will see what the garage says but most of the info seems to relate to an earlier model but i still probably relevant.

[V]

All modern vehicles after 2001 have an OBD2 port. With the help of a little Bluetooth ODB2 scanner and a compatible smartphone app you can read the stored Diagnostic Trouble Codes of any 21st century vehicle yourself without having to pay a garage to do this. If you have the DTC information before you seek the assistance of a garage, you can research the problem before spending money on it.

 

[neal]

23 minutes ago, V said:

All modern vehicles after 2001 have an OBD2 port. With the help of a little Bluetooth ODB2 scanner and a compatible smartphone app you can read the stored Diagnostic Trouble Codes of any 21st century vehicle yourself without having to pay a garage to do this. If you have the DTC information before you seek the assistance of a garage, you can research the problem before spending money on it.

 

And JScan is an app that can do that for you, it does list GC, not sure if it’s the correct one.

it’s a great app, at least for JK

 

[honda]

Thanks both, quite a lot to take in but I will definitely need to get a scanner, trouble is which one is compatible so I will need to do some research also find the app.

 

Really helpful, much appreciated. 

[neal]

12 hours ago, honda said:

Thanks both, quite a lot to take in but I will definitely need to get a scanner, trouble is which one is compatible so I will need to do some research also find the app.

 

Really helpful, much appreciated. 

@honda if you are going to look at the JScan app, which you can download for free on IPhone and android, do that first.

 

It list the obd2 devices that have been tested and ‘approved’ for the app.

[honda]

Thanks again, all help appreciated