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It went in for the MOT (car check) and failed on emissions.
Prior to Mot,car ran fine, although the CEL came on occasionally but would go out soon after.
After a bit of investigation they discovered the front and rear 02/lambda sensor were wired the wrong way around.
I had to replace the gearbox a while ago, so may have got them wrong, but would have expected the CEL to permanently display?
they swapped them around, but had issues with the front sensor, heating circuit.
They replaced the front sensor, it then passed emissions.
shortly after, and the CEL is permanently showing, with fault P0135 - 02 sensor heater circuit bank 1 sensor 1.
If i reset the fault, it cames back on within seconds.
Then today the speedo was being random sometime working, sometime not, at one point when it was not working the car cut throttle.
its also showing fault code P0500 car speed sensor 1.
How was it wired incorrectly, was there any wires that were cut?
The connectors for front and rear sensors are different (one male and one female) so shouldn't be possible to mix them up.
It is however possible to connect the two connectors that comes from the car together which often results in a fried ecu.
Thanks guys, I've been away a while and need to sort this!
Ive had a look at the ground on the back of the cylinder head, and its defiantly not there!
I have a feeling when i did the head gasket 18 months ago, i couldn't get it back on and bolted it to the water inlet that bolts to the intake manifold with 2 bolts.
Its got 0.03 ohm resistant from the connector directly to battery negative, so it can't be too bad a connection?
you can just about see it here:
Would this cause the issue, would it not be a good ground here?
The electrics seem to have gone haywire, as the power steering works occasionally, speedo works sometimes, CEL is on permanent showing fault with the C0 sensor.
Starting to wonder if its the ECU fried if its not the ground.
Going to get the car on some stands in a bit and check the sensor connectors.
Ok, just been under, and both Lambda sensor looks have Grey Covers, not Blue & white?
However one has male connector the other female connector, so not possible to mix up, unless id plugged the loom into itself.
However if i had done this, i would have expected the CEL to have come on at the time?
However after inspecting the speed sensor, I've discovered the loom has been butchered!
Maybe some form of resistor? it was wet inside insulation tape!
The black thing is heat shrink.
You should move the ground to the correct location if possible, measuring it like that does not tell much.
I've no idea what that chip is, maybe some top speed limiter removal if your car is a Japan import maybe?
Really stupid placement nonetheless.
The car now drives like a completely different car!
Steering works perfectly, nice and firm at speed, and light at low speed. And completely smooth, as was a little notchy before.
Speedo is perfectly smooth, although in KPH. I will look at fitting a converter after the ecu so it doesn't effect the steering!
The engine feels much smoother and VTEC kicks in much smoother, it wouldn't always kick in before or at the right time.
However i still have the P0135 (02 sensor) fault, ive checked the sensor and its fine, and is a brand new part.
So im thinking i must of fried the ecu when i mixed up the o2 connectors! (Why is this even possible!)
But luckily looking on ebay and there was 1 99 JDM ECU for £80. Which will hopefully slot straight into my 01.
And im pretty certain the JDM's do not have immobilisers, so shouldn't need programming??
The car does have an immobiliser, but it is one of those sticks you press agains a sensor and im sure is part of the viper alarm?
Hope fully this will fix the last of my issues...
CEL light issue?
