How will limp mode clear ?

[Ian Stan]

Hi again

In the absence of fault codes how would a 1.6 come out of limp mode ?

The only code I get now is P1351 Pre/post warm up relay, would a fault with the glow plug system perpetuate limp mode until rectified? My borrowed “Launch” fault code reader has the facility to test the relay and it can clearly be heard clicking . Would a duff plug be recognised by the Ecu ?

Thanks

[GiveMeABreak]

No -there are no limp modes without a fault code, as to do this, the engine ECU has to enable a specific backup mode dependent upon the fault and what type of downgrade mode (if any) is dependent upon the affected system. Glow plugs don't trigger a limp mode. They are only used when necessary in pre-post heating and occasionally where needed to assist with DPF regeneration.

P1351 is a common fault - and means the pre-heating circuit relay is supplied, but the plugs are not. The preheating control unit indicates that the relay is open despite being commanded to close by the ECU for 5 seconds.

This is an extremely common fault code repeated here on the forum for many HDi vehicles and is common as muck. I have had it on mine since I've had the car and ignore it with no issues.

[Ian Stan]

Thanks Mark


Will limp mode clear after a few miles trundling up and down ?or several start stop sequences ?

[GiveMeABreak]

Any downgrade mode will be triggered by a fault code as said - and by the same token the specific fault triggering the downgrade mode will also have conditions for clearing itself - either once cause is remedied or when certain driving conditions are met.

[Ian Stan]

Thanks Marc