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A CF2 V6 engine & ECU (but not in a 166 any more....).

This is in the project I'm building at the moment. ECU etc is all stock. I've been completing the cooling system on this project recently and running the engine for a bit longer than just a few seconds as I did some time back when I first checked all was working. It's been running long enough to get properly warm, on a few occasions now.

While checking all was well, I ran up MES and found it's throwing a P0135 code, says the 'probe output too high' (sorry, haven't made a note of the exact words - will do that tomorrow) and keeps cycling the heater power on & off every second or thereabouts. Lambda output voltage looks sensible, engine is running well enough and once it is warmed up a wee bit, runs closed loop as well, but obviously, I want the heater working as it should. This fault isn't bringing on the MIL - it states it isn't as well, presumably doesn't consider it a sufficiently bad fault.

(I'm pretty certain it wasn't generating any codes when I first ran it, albeit very briefly, about a year ago).

I've checked the 12V switched power to the probe is good, and my last check was to connect a 21W bulb in place of the lambda heater - this could be seen pulsing on & off, with the engine running, in time with the diagnostic showing it switching on & off. This suggests to me that all the parts are in place and working as they should - wiring, 12V supply and the ECU itself. Interestingly, no error code showing now. Also interesting to me was that the ECU drives the heater directly, rather than through a relay.

Lambda is new (but not a genuine part), heater measures about 5 Ohm cold, which seems reasonable??

Any thoughts?? I'm wondering if I should just buy a genuine Bosch probe and try that. I tried to save the original probe out of the donor but simply couldn't get it out of the old exhaust so it's long gone.

TFL
 

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Discussion Starter #2
Bit more testing, swapped the probe for a dead one I took out of the Jeep a while back (it had become sluggish). Fine. No fault code.

So, new genuine Bosch probe on order. See if that sorts it.
 

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Just to close this - new, genuine, Bosch probe arrived today, fitted, tested, all good.

Moral? Beware non-branded too-cheap-to-be-true Lambda probes! At least the duff one was cheap enough it doesn't hurt too much that it's garbage. I really should know better though. Only buy known brands. NGK (NTK), Bosch, Denso.
 
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