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Vauxhall Vectra C 1.8 Dual fuek Z18XE - Code P0170 - APJ52

I have been having trouble with this code ( P0170 Fuel Trim Malfunction (Bank 1) - OBD Codes ) on my car for ages.

I have had the Lombda sensor changed ,cleaned the MAF reset the code it lasts about a day and comes back on with the same error.

The garage has tested the MAF flow before cleaning and after cleaning and not much change.

He seems to be a bit out of depth now and it is costing me every time I go Back.

So please could anyone HELP me, I'm struggling.



Vauxhall Vectra C 1.8 Dual fuek Z18XE - Code P0170 - skidpan

Try a different garage. Maybe its best to use a Vauxhall dealer with a fairly unique car like yours.

Vauxhall Vectra C 1.8 Dual fuek Z18XE - Code P0170 - APJ52

Thanks Skidpan,

I have asked Vauxhall and they do not service the Duel fuel vectra now.


Vauxhall Vectra C 1.8 Dual fuek Z18XE - Code P0170 - Railroad.
I'm not totally familiar with how the system works specifically on your car, but fuel trim is the ECM's rich/lean correction functionality. Your engine needs to run rich and lean either side of the ideal (known as the stoichiometric) to produce the necessary gases for the catalyst to work. I'm guessing that the ECM is unable to control the fuel trim whilst running on LPG for whatever reason, and consequently generating a fault code. Does the engine use the same injectors whilst on LPG or is there a separate injection system for it? If it is seperate then the ECM may not detect any change via the O2 sensor in response to fuel trim, hence the code.

Not sure if this is actually the case. I'm thinking out loud really. Does the problem also exist when running on normal unleaded?
Vauxhall Vectra C 1.8 Dual fuek Z18XE - Code P0170 - hardway

I'm with Railroad on this one,

Disable the dual fuel so it only runs on petrol.and I mean dissconnect the fuel feed so it can not influence the running.

Then re test.

Still throwing up that code?

At least you know where it is/isn't

That code

I'd be looking for induction leaks,

the code refers to the ECU's inability to richen up the mixture,

as far as the ECU is concerned it's maxed out on the short term fuel trim.

and it's still too lean.

So back to an induction leak,

air that hasn't been measured by the MAF is getting in to the engine,

Somewhere between the AFM and the engine is an induction leak.

You can test this by letting some gas from an unlit blowtorch into the induction system while monitoring the lambda out put on a scanner,

It should now read high lambda as the extra fuel in the form of gas riches up the mixture.

This will tell if the ECU is capeable of reponding to the lambda output readings.

And though I hate jumping to conclusions I have a hunch that the intake plenum chamber may be the fault.


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