Mechanics

CHECK ENGINE LIGHT ON

1992 Isuzu Bighorn • 270,000 miles

I have a V6 petrol Bighorn and 75% of the time I use it the Check Engine light comes. It stays illuminated as long as have the foot on the accelerator and goes out when coasting. There is no noticable affect on the running performance when light is on. I have tried to get a diagnostic code flashed (OBD1) but it flashes the code for no fault found.

This happens after about 20 minutes of driving which made me initially think it was a problem with the O2 sensor. Apparently this could happen with unheated sensor models as the sensor is locked out by the ECU until the exhaust is up to temperature, but I think I have a heated verson.

Any clues
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Edave12
October 9, 2012.




Have you tried using a scan tool to read the codes?From when the light turns on code be a egr issue.
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Saturntech9
Oct 9, 2012.
Maybe manual retrieval of the trouble codes might show something.

KHLow2008
Oct 10, 2012.
Sorry, I meant to say if it does not show anything, you can leave the system in diagnostic mode and go for a test drive till the light shows. It might show something.

Alternatively, check for a bad ground circuit for the ECM.

KHLow2008
Oct 10, 2012.
Running in the diagnostic mode, had thought of doing that so will give it a go. The other thought was since the light goes out when coasting to a stop may be why no fault codes show up. I might try hitting the throttle before stopping so the light is on then turn the engine off, hopefully the light will come on and I will get a fail code.
Will let you know how we go.

Tiny
Edave12
Oct 10, 2012.
Wholemkt13

Hope you have enjoyed your brief stay here.

KHLow2008
Oct 10, 2012.

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