Error code P1166….

[Wellhappy]

Following on from my other post getting this through it’s MOT failing on emissions .. we cleaned the egr and put better fuel in after a clean out and took the car for a high rev play and this popped up but is intermittent and comes off and I’m off on a nice run out ect ?? Could it be the wiring or the actual sensor itself as this has never come up before ?? I take it that if it’s the sensor it’s the one in the manifold ..

[Scott560]

Was the lambda wiring clipped back properly? It seems strange it would fail now unless it was mishandled.

I would check the wiring isn't burnt out/shorting on the manifold and that the wiring/connector is proper. There probably is a fuse associated with the heating circuit, I would double check the under bonnet fuses.

If everything looks OK, I would further check the sensor for continuity on the heater circuit pair, but I couldn't tell you the wire colours off the top of my head (normally 4 wires, 2 for heater, 2 for sensor).

If the circuit is open - sensor heater ist kaput - get a new 02 sensor and be careful when fitting it.
If there is continuity in the sensor - wiring to it might be dodgy, or the heater fuse has blown.
If all that checks out OK - I would clear the code and drive normally and see if it sorts itself out. Normally this code would indicate a failed sensor though...

I have seen holed exhausts cause fuel trims to be held up too high - and the only way to get it back to normal was to clear the DTC code, run the car around for a bit (normally, no full throttle, normal town driving), reset the code, and repeat that 4 or 5 times until the trims lowered enough for it to sort itself out, but that was for a different code.

[Wellhappy]

Was the lambda wiring clipped back properly? It seems strange it would fail now unless it was mishandled.

I would check the wiring isn't burnt out/shorting on the manifold and that the wiring/connector is proper. There probably is a fuse associated with the heating circuit, I would double check the under bonnet fuses.

If everything looks OK, I would further check the sensor for continuity on the heater circuit pair, but I couldn't tell you the wire colours off the top of my head (normally 4 wires, 2 for heater, 2 for sensor).

If the circuit is open - sensor heater ist kaput - get a new 02 sensor and be careful when fitting it.
If there is continuity in the sensor - wiring to it might be dodgy, or the heater fuse has blown.
If all that checks out OK - I would clear the code and drive normally and see if it sorts itself out. Normally this code would indicate a failed sensor though...

I have seen holed exhausts cause fuel trims to be held up too high - and the only way to get it back to normal was to clear the DTC code, run the car around for a bit (normally, no full throttle, normal town driving), reset the code, and repeat that 4 or 5 times until the trims lowered enough for it to sort itself out, but that was for a different code.

brilliant thank you sooo much fella, this has helped no end and will go check everything mentioned, that’s what I love about this forum ! Everyone is so helpful

[Scott560]

Everyone is so helpful

It's only helpful if it fixes it!

[Wellhappy]

Everyone is so helpful

It's only helpful if it fixes it!

let us pray