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Unsure of repair to Jeep GC


Surfer

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We took the 2012 Jeep Grand Cherokee Summit to the a Jeep main dealer, but not out usual one for Engine Management Light issue. They read the code P0741 and another code for Glow plug 5 and told us that for them to rectify the issue all the glow plugs needed changing. This did not rectify the issue.

The alternator went pear shape and more expense as it needed replacing at nearly £1500. Over the phone they quoted £1223 to which I agree, but that price was without VAT so they caught another sucker!  They also told that to rectify the P0741 fault code that that the transmission fluid and filter need changing, but Jeep states that the filter does not require changing and transmission fluid was changed less than 12000 miles ago.

Anyway when we got the vehicle back EML not on. Towing up the M5, M42 and M6 I could feel the car surging and shortly after coming off the M6 onto an A road the EML came back on so still the same fault that the Jeep went to the garage originally. I did notice that when the vehicle got the flat spot the revs dropped quite considerably. Normally I would put it down to a dirty fuel filter starving the engine, but with modern engines and EMLs I am unsure.

Having gone through everything it seems that I have very little recourse for a claim with the dealer so have abandoned that idea. However as we still have the same issue with the flat spot or surging I think I will have to bite the bullet and pay our normal dealer who are in Oxford the £100 for the diagnostic which will be the third one in less than 2 months! I am hoping the our normal Jeep dealer can access the previous diagnostic check.  I am sure that they will resolve the issue.

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For a lot less than £100 you can get your own diagnostic software and run the diagnostic yourself 👍 . It really is a very worthwhile investment.

Edited by TimC
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We are in Worcester and I do not know of any inde Jeep specialists near us.  I do have a OBDII which shows the same fault code as the expensive diagnostic, but they need their own diagnostic first.  Looks like another unnecessary expense.

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If I have read this correctly, you have:

  • EML currently lit
  • Code P0741 read from your own OBD2 scanner
  • Recently changed transmission fluid and filter by dealership technician
  • Transmission fluid topped up correctly by dealership technician

I have a few questions:

  1. What do you mean by the term 'flat spot', can you be more descriptive?
  2. What do you mean by the term 'surging', can you be more descriptive?
  3. Does the fault only occur when towing your caravan?
  4. Does the fault only occur going uphill?
  5. Does your automatic transmission shifter have manual selections E.g 3, 2, 2-1, L?
  6. What is listed on the invoice for the P0741 fix?
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4 hours ago, V said:

If I have read this correctly, you have:

  • EML currently lit
  • Code P0741 read from your own OBD2 scanner
  • Recently changed transmission fluid and filter by dealership technician
  • Transmission fluid topped up correctly by dealership technician

I have a few questions:

  1. What do you mean by the term 'flat spot', can you be more descriptive?
  2. What do you mean by the term 'surging', can you be more descriptive?
  3. Does the fault only occur when towing your caravan?
  4. Does the fault only occur going uphill?
  5. Does your automatic transmission shifter have manual selections E.g 3, 2, 2-1, L?
  6. What is listed on the invoice for the P0741 fix?

 

The car seems to lose power and the revs drop.  At other times despite pressing the pedal the car does not accelerate and then suddenly kicks in.  This fault seems to occur whether in cruise or not and has happened when not towing.  Happened quite a number of times today while towing the caravan back.  It does very occasionally occur when not towing.

The EML came when towing to our destination on Saturday, but on Sunday and this morning it was off.  Only comes on when I have been towing for about and hour or more and came on after towing for about an hour on the way back home today.  I tow at about 58mph increasing to 60mph when over taking a HGV. 

I can use manual mode and never thought of trying it in manual mode when it was occurring.  Nothing mentioned on previous invoice when I originally took it in for the P0741 repair.  Second time around the new Jeep dealer said that transmission fluid and filter required changing to start eliminating the issue.  To date the Jeep dealer has not fixed the issue and in my opinion it is now starting to get dangerous.

 

BTW today I read the OBDII on our return home and the P0741 fault code was there however an archived fault code P2002 also showed up.  This relates to the DPF but as it is archived I assume it has been rectified at some point in the past?  Prior to this archived fault code coming up I used a diesel fuel additive for cleaning the engine, plus I filled up with premium diesel.  Maybe there is an issue with teh fuel filter, but I have no idea how to access it.

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37 minutes ago, Surfer said:

The car seems to lose power and the revs drop

Could this be that the torque converter is locking normally to enable direct drive? This will lower the revs as the torque converter will no longer be slipping. The engine crankshaft will see the full load of the driveline without any torque multiplication from slippage. If when on cruise control, the Jeep cannot maintain direct drive, it will downshift and upshift as soon as it can. Sometimes, this can appear like constant downshifting and upshifting which is what I thought you may have meant by surging. If so, cancel cruise and manual downshift, returning to 'D' when you think the engine wont be labouring. See if that helps.

 

I am amazed that your invoice doesn't mention 'Investigate P0741 fault, wiring to torque converter clutch solenoid, solenoid operation'. Perhaps they thought changing the fluid would do that for them.

 

I think it is time to take the vehicle to an automatic transmission specialist. The one near me in Norfolk doesn't charge for a diagnostic code check, but plenty in other areas do. The P0741 needs to be properly investigated. The wiring and connectors need to be checked and the solenoid operation should be checked on the car (or off it if it fails). A replacement solenoid may be necessary. There could be other problems like a bad transmission hose restricting flow, damaged or blocked transmission cooler. On the engine, a leak on the induction side of the turbo, like a hose fault causing a loss of boost pressure which might be the surging you are experiencing.

 

Another thing that may be an issue is that your original equipment transmission cooler may be too small for the load of your caravan. If a specialist recommends installing a thermostat controlled supplementary or a larger replacement cooler it would be worth considering. The transmission fluid needs to get up to operating temperature for the torque converter lock-up to work. On my Jeep I think the minimum temperature is 40 DegC and the maximum of the normal range is 90-95 DegC. Transmission fluid gets damaged over 105 DegC so you can see that there isn't much margin if the fluid is already running hot.

 

I have no experience of ATGL in Gloucester, but worth giving them a call.

I can recommend STA in Aylesbury. They have built transmissions for me in the past.

 

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Thanks for your valued input.  Considering that in the past month we have spent over £2000 on the Jeep I am obviously reluctant to be spending a lot more.  Granted of that £2000+ about £1473 was for replacement alternator, it still means that we have spent over £550 for the P0741 issue to be resolved and are no nearer resolving it than when it first went to the Jeep dealer in question with the issue.  If it is the solenoid I dread to think of the cost.  Also if it is the DPF playing up that is another issue!

 

We have been using the Jeep for towing the same caravan for the past 4 years and have had no issues.  Best tow car we have ever had!  It is almost as if the engine is starved of fuel and then fuel gets through hence the surge? 

 

Reading up on the P0741 fault code it seems there is no relation between the fault code and the vehicle losing power and then surging.

Edited by Surfer
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I have been reading a few TSBs on the V6 petrol model that describes the engine losing power on 4-3 downshifts when towing. The transmission shifts into neutral for too long between 4 and 3. No mention of this being an issue on the CRD. Perhaps it was never discovered. Also found some temperature related issues when towing, again no mention of CRD.

 

I found this TSB regarding software changes to the torque converter lock-up sequence that could be relevant.

 

I found reports of the pressure pipe going into the DPF leaking. On early models it is a meta pipe part of the DPF. On later models it is a separate part. Replacing it fixed the power loss the owner was getting with a P2002.

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When you mention early models, which years would this be?  I suspected perhaps a DPF issue hence using the premium fuel however travelling at 58mph on the motorway towing should clear the DPF.  If the whole DOF needs to be replaced that is a very expensive repair. 

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I think by earlier model it was made before FCA takeover, later model made after FCA takeover.

 

The pipe leak was detected by the presence of sooting on the transmission. Depending on what the problem was, it would be worth trying a clamp on sleeve with some hardening exhaust paste over the leak, or welding especially if at a pipe junction.

 

I just found this info that I did not know before about the Jeep DPF regeneration. It does not get triggered automatically if there are any diagnostic codes stored.

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The fault code P2002 came up as "archived" which seems to indicate that it was in the past, but it has never come up before when using the OBDII and same app?  Jeep garage was supposed to have cleared all the codes when they replaced the alternator. 

I have never had a message come up regarding a DPF issue, although symptoms are similar with intermittent loss of power which is noticeable when towing.  Fuel consumption seems to be normal.  No smoke of any colour from the vehicle.  Car definitely not sluggish if I put my foot down.  I only fill up with Esso fuel.

 

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I have contacted Unity Oxford and the car is booked in for the 22nd Aug as in my opinion it could be dangerous to drive with intermittent loss of power.  Rather give them the cash than the other Jeep stealer.

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