Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Brynjaminjones on November 02, 2015, 09:18:53 AM

Title: 4.0 ZJ Dash Lights and Fault Codes
Post by: Brynjaminjones on November 02, 2015, 09:18:53 AM

Good Morning 'Dastards,

This morning after a slow dawdle along the motorway at 50mph, the check engine and ABS lights came on in the ZJ.

I ran the key on-off trick diagnostics and pulled codes 12 and 51. The descriptions I've found for those are:

• 12 Direct battery input to PCM was disconnected within the last 50 Key-on cycles.
• 51 A lean air/fuel mixture has been indicated by an abnormally rich correction factor. (O2 sensor)

I find it a bit strange though for a few reasons:

• The ABS has never worked since we've had the ZJ, but the dash light has always stayed off after start-up checks
• The battery hasn't been disconnected or flat for months
• Why is there no code regarding the ABS?

For the record, the lights came on whilst running on gas, and were still present when restarted on petrol.

Can anyone offer any advice on where to start with this?

Title: Re: 4.0 ZJ Dash Lights and Fault Codes
Post by: wildwood on November 02, 2015, 01:23:40 PM

Disconnect battery for half hour,and try again...... Sometimes works.

Make sure you have radio code with you.

Title: Re: 4.0 ZJ Dash Lights and Fault Codes
Post by: Brynjaminjones on November 02, 2015, 07:21:31 PM

Cheers Jez! I disconnected the battery, then did the PCM reset trick and all is back to normal!

The lights are still off after a good 80 miles since

Sent from my HTC One M8s using Tapatalk

Title: Re: 4.0 ZJ Dash Lights and Fault Codes
Post by: Bubba on November 04, 2015, 06:57:04 AM

lpg does trigger the engine light with some installations i had this on larry the gay zj

Title: Re: 4.0 ZJ Dash Lights and Fault Codes
Post by: Brynjaminjones on November 04, 2015, 10:18:07 AM

Thanks Kev, I hadn't realised that Larry was on gas.

I've got it in with an LPG specialist today, so hopefully they'll find anything that's up with it.

Sent from my HTC One M8s using Tapatalk

Title: Re: 4.0 ZJ Dash Lights and Fault Codes
Post by: Bishops Finger on November 04, 2015, 02:31:17 PM

LPG issues....

Title: Re: 4.0 ZJ Dash Lights and Fault Codes
Post by: Brynjaminjones on November 04, 2015, 03:20:03 PM

I've got the ZJ back from the LPG specialist, and nothing's really wrong with it. It turns out that it just needed the fuel mapping altered after having different LPG injectors fitted.


Two hours of labour while they adjust and road test it, and all of the stumbling issues are gone, and so far fuel economy is massively improved too  8-)

Title: Re: 4.0 ZJ Dash Lights and Fault Codes
Post by: JamesH on November 05, 2015, 05:47:42 PM

 :icon_super:

Title: Re: 4.0 ZJ Dash Lights and Fault Codes
Post by: bigjeepzj on November 05, 2015, 06:56:23 PM

 :icon_super:

Title: Re: 4.0 ZJ Dash Lights and Fault Codes
Post by: Dave69 on November 06, 2015, 09:14:42 PM

Quote from: Bishops Finger on November 04, 2015, 02:31:17 PM

LPG issues....

ther you go Sir, no issues with LPG

Title: Re: 4.0 ZJ Dash Lights and Fault Codes
Post by: Bishops Finger on November 06, 2015, 10:45:35 PM

Neither of my ZGs had santa fuel issues but then again...