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-   -   UK 05 model Hemi DTC (http://www.jeepgarage.org/f181/uk-05-model-hemi-dtc-34551.html)

baz2328 01-23-2012 08:55 AM

UK 05 model Hemi DTC
 
Hello, recently had failure to start on a number of occaisions, turn key and clunk - no start. Repeating key action would then start engine. DTC shows P1521 pending, also getting messages flashing up about 'service brake system' with a chime but this goes after a couple of seconds.

Seen issues on forum due to failing batteries, dont know how old battery is as only had jeep for 2 months. Is it worth getting battery load tested as 1st step, if ok any suggestions?

Thanks

dr.lee.baugh 01-23-2012 10:37 AM

Re: UK 05 model Hemi DTC
 
Others have had the battery load tested and it checks out, but it still is the cause of the problem - you can try it and see how it tests, but just because it passes doesn't mean it's not the cause!

The battery resulting in these weird electrical issues seems to happen a fair bit, so I would try swapping in a fresh battery and see if that solves your problems - especially if you don't know when it was replaced last.

Worst case, you get a nice new battery.

Hope it works out!

dr.lee.baugh 01-23-2012 10:47 AM

Re: UK 05 model Hemi DTC
 
Oh, and DTC P1521 can be tripped by using the incorrect oil viscosity.

If you haven't performed an oil change since you purchased it, I would take it in and MAKE SURE they use 5W-20...a lot of shops still insist the 30 weight oil is fine with the Hemis (which it absolutely is not)...

"P1521–INCORRECT ENGINE OIL TYPE
When Monitored:
Engine Running.
Set Condition:
Using the oil pressure, oil temperature and other vital engine inputs the PCM can determine the engine oil
viscosity. Incorrect viscosity will effect the operation of the MDS by delaying cylinder activation.
Possible Causes
INCORRECT ENGINE OIL TYPE
ENGINE OIL CONTAMINATION
ENGINE OIL
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1. ACTIVE DTC
NOTE: Review the customers oil change history. Make sure the customers is using the correct engine oil
viscosity. If the incorrect oil is being used, change the oil, using the correct engine oil viscosity.
Ignition on, engine off.
With the scan tool, read DTCs.
Is the DTC active at this time?
Yes >> Go to 2
No >> Test Complete.
2. ENGINE OIL
NOTE: If any engine oil pressure or oil temperature DTCs set along with P1521, repair them before continuing
with the P1521 diagnostics.
The following conditions must be checked.
OEM recommended oil viscosity is being used.
Customer is following the oil change schedule.
Check the engine oil for contamination. (i.e., fuel and/or engine coolant)
Internal engine condition that may effect oil pressure.
Were any of the above condition found?
Yes >> Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No >> Change the engine oil using the correct oil viscosity.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE"

baz2328 01-23-2012 12:50 PM

Re: UK 05 model Hemi DTC
 
Thanks very much, will do battery and oil.

2005JGC 01-23-2012 03:02 PM

Re: UK 05 model Hemi DTC
 
Sounds like a starter to me, VERY common failure on the 5.7l. Sounds like worn/damaged solenoid contacts, the click you hear is the solenoid closing but if the contacts are damaged to the point where they dont allow electrons to flow you get the click with no further noises... repeated key cycles opens and shuts the solenoid repeatedly which can encourage good contact leading to the vehicle starting.

dr.lee.baugh 01-23-2012 04:19 PM

Re: UK 05 model Hemi DTC
 
Quote:

Originally Posted by 2005JGC (Post 558849)
Sounds like a starter to me, VERY common failure on the 5.7l. Sounds like worn/damaged solenoid contacts, the click you hear is the solenoid closing but if the contacts are damaged to the point where they dont allow electrons to flow you get the click with no further noises... repeated key cycles opens and shuts the solenoid repeatedly which can encourage good contact leading to the vehicle starting.

Thanks for your expertise (once again!), it's great to have someone with your background in the forum.



Do failing starters often lead to the erroneous DTCs and messages as well?

That is why I had thought of the battery first - but I love it when I learn something new about our vehicles.

baz2328 01-28-2012 06:23 AM

Re: UK 05 model Hemi DTC
 
Thanks for the info re starter, are the solenoids service items or is it combined and do I need a complete starter unit?

Thanks

2005JGC 01-30-2012 01:21 AM

Re: UK 05 model Hemi DTC
 
Quote:

Originally Posted by dr.lee.baugh (Post 558903)
Thanks for your expertise (once again!), it's great to have someone with your background in the forum.



Do failing starters often lead to the erroneous DTCs and messages as well?

That is why I had thought of the battery first - but I love it when I learn something new about our vehicles.

A failing starter should not cause erroneous DTC's. They may be linked but they are far enough apart that I would assume they are separate issues. Interwebz diagnostics is not an exact science but a click on a starter is a pretty solid indication that at the very least the starter solenoid is failing.

Your thought on the P1521 is where I would start for sure.

Thank you btw, I like to help out where I can.

Quote:

Originally Posted by baz2328 (Post 562216)
Thanks for the info re starter, are the solenoids service items or is it combined and do I need a complete starter unit?

Thanks


Solenoids on most modern vehicles are integrated into the starter itself, as is the case with the Grand Cherokee. The starter will need to be replaced. Hopefully you have VERY small hands and long arms, that or A LOT of patience if you want to tackle it yourself, on Hemi's I typically drop the front differential down to allow more room (not a lot mind you)


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