2011 RC Colorado 3L TD Check Engine Light

KA74
Posts: 16
Joined: Mon Oct 11, 2021 11:33 pm

Re: 2011 RC Colorado 3L TD Check Engine Light

Post by KA74 »

EGR code is back.
Apparently a loose connection according to the code.
Can reset it but it keeps coming back.
Been to the auto elec, as put a new genuine EGR on and same error.
They have tested plugs and wires and think it is the Computer. They reckon to remove and get computer looked at.
Has anyone encountered this?
Regards
KA
mydmax
Posts: 1943
Joined: Sat Oct 12, 2013 8:36 pm

Re: 2011 RC Colorado 3L TD Check Engine Light

Post by mydmax »

KA74
Because of the possible age/KMs of the vehicle, have you considered the EGR cooler may be choked up with carbon and causing restriction of the EGR exhaust gas flow and the ECU is seeing insufficient flow and creating a code. Yes, resettable but still present under certain conditions and the threshold is passed.
Has the auto elec actually tested the ECU plug end wiring for reliable continuity to the EGR stepper motor plug? I think not.
Has the auto elec actually removed the plugs and inspected the pins and connector socket ends with a high power magnification and LED light source so any anomaly can be detected. Recently I had a Corolla fuel pump give trouble. The problem was the socket sleeves in the connector were much larger than the fuel pump pin cross section. Mostly touched but sometimes NOT. Simple but difficult to find unless you think outside the box. It is easy to recommend ECU investigation if their competence in problem solving isn't up to the required standard. If your engine wiring loom has sagged and moves around a bit it may have fractured and intermittently stops touching. Any loose wiring may be the area to examine after unwrapping the loom section.
Remember, any slight corrosion between wire and crimped socket pins may be the cause and may require removing each socket pin one at a time so integrity can be confirmed. A "GOOD" auto elecahould be able to achieve that.

PS. in my opinion. If the ECU is faulty it will remain that way and not change in and out of function. It simply follows the instructions supplied or not supplied to it.
KA74
Posts: 16
Joined: Mon Oct 11, 2021 11:33 pm

Re: 2011 RC Colorado 3L TD Check Engine Light

Post by KA74 »

Thanks Mydmax,

The autoelec had the car today for a few hours.

Cannot recall the code error number P0004? The connection one.

He checked the pins on the main plug to the egr and closed the pins to ensure they were connecting.

The next stage is to check continuity of all the wires from the EGR plug to wherever they go and then check the ECU.

The vehicle actually runs fine, normal fuel consumption and power feels same. Just the light on and (maybe my imagination) a slightly rougher idle.

Autoelec doesn't want to do it before Christmas as too busy and worried if the ECU is an issue it will take a few weeks to get back and there is the christmas closedown.

Frustrating, but they appear to be going down the path you suggested of checking all the wires for continuity, but at the next visit.

Will update when i know more, sounds like late January now.

Regards
KA
Mike C
Posts: 57
Joined: Fri Dec 10, 2021 7:13 am

Re: 2011 RC Colorado 3L TD Check Engine Light

Post by Mike C »

For what it's worth , there is no fault code P0004 listed in the Haynes manual for any model D-Max.
mydmax
Posts: 1943
Joined: Sat Oct 12, 2013 8:36 pm

Re: 2011 RC Colorado 3L TD Check Engine Light

Post by mydmax »

KA
Has the EGR valve body been removed and cleaned while off the engine? The problem may be carbon buildup in the valve and not allowing sufficient EGR flow to be detected as normal. Don't assume it is solely an electrical problem.
What is happening can be electrical fault and wrong signal or could be be wrong flow of exhaust gas causing ECU to generate a code.
Mike C
Posts: 57
Joined: Fri Dec 10, 2021 7:13 am

Re: 2011 RC Colorado 3L TD Check Engine Light

Post by Mike C »

I used to get low EGR gas flow codes when I was pulling a boat up a ramp and had an EGR restrictor plate plate fitted but they were easily cancelled by OBD2 Autodoctor and didn't recur until the next time I retrieved the boat. This led me to remove the plate and fit a catch can.
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