Running lumpy, engine management light and fault codes! Help please!

[chris_sri]

Well, my 2003 Vectra 1.8 sri dual fuel has been running rough recently, but only from start up when cold and within a minute it's running fine. Today the engine management light came on and is reporting fault codes 2103, 0170, and 0565.

It runs on petrol on start up, and after a minute or so runs well, and then switches to LPG as normal. It runs fine in both petrol and LPG mode. The problem only occurs when the engine is stone cold in any outside temperature.

Could anyone shed any light?

I don't think my engine has an EGR?

Could it be a MAF sensor problem?

Thanks guys, and as always, any advice appreciated.

[Robsey]

P0170 - Fuel Trim Malfunction (Bank 1)

P0565 - Cruise Control On Signal Malfunction.

B2103 - Antenna Not Connected ? - Don't think this is right, but I have no listing for P2103


Does this help in any way?

Yes your car will have an EGR valve!! and it will have either a MAF or MAP sensor.

MAP and MAF only operate to control fuel mixture when accelerating and usually at full operating temperature.

Lumpy idle when cold, could be a dodgy Coolant temperature sensor

[John C S]

I wouldn't worry too much about this code:


P0565 - Cruise Control On Signal Malfunction.

I get this on mine occasionally and it doesn't even light the engine management light.

Activating the cruise control via resume function on a long straight road 15-20 times is enough to clear this.


It is caused when the resume button on cruise doesn't quite make contact.

[chris_sri]

I've found out that code B0565 is 'Coolant temperature indicator circuit malfunction'.

How do you differentiate between P, B, C and U codes?

So if i've got a 'B0565' coolant temp sensor problem, then that's causing the cold idle problem and that, in turn, could be causing the P0170 Fuel trim malfunction?

[Robsey]

If you have a Vauxhall / Opel / Holden / Saab specific diagnostic tool, then it will possibly give the prefix letter....

Most vauxhall codes are P prefix, but there are others listed on general EOBD II diagnostic tools...B, C, P and U just depends on the sales make etc.

[Robsey]

I've found out that code B0565 is 'Coolant temperature indicator circuit malfunction'.

How do you differentiate between P, B, C and U codes?

So if i've got a 'B0565' coolant temp sensor problem, then that's causing the cold idle problem and that, in turn, could be causing the P0170 Fuel trim malfunction?

This sounds the most plausible fault...also a coolant temperature sensor is quite a cheap component to buy.

Check connectors for cleanliness / corrosion first, before paying out for a sensor / sender.

[DaveW555]

I'd go for temp sensor first and if that doesn't cure it probably a maf sensor, its usually maf sensor that flags the 0170 code.

[ChrisBilly]

Where is the coolant temp sensor on 1.8's?

[chris_sri]

Where is the coolant temp sensor on 1.8's?

Its fitted into part of the thermostat housing.

[Robsey]

I'd go for temp sensor first and if that doesn't cure it probably a maf sensor, its usually maf sensor that flags the 0170 code.

MAF sensor only throws up the code when accellerating.

At cruise and idle, the Lambda sensors control all the emissions etc.

If the car feels like it is running on just three HT leads, then in order of cost effectiveness / cheapness

1) Check for air leaks around inlet manifold
2) Check HT Circuit is clean and dry and working fine
3) Clean the MAF sensor if it is a hot wire device (gently using carb spray)
or
..if it is a vacuum controlled item (MAP sensor) then check the vacuum hose is not split
4) Check the Coolant Temp sensor and replace if required.