Ok, I have a problem with the instrument panel throwing up a MIL lamp when the RPM exceeds 3000rpm.

The Rpm meter drops to Zero and throws up what appears to be a ABS lamp.

All faults are reset after ignition is turned off /on.

Assuming the fault to be in the instrument panel, this was put into diagnostic mode and a full sweep of the instrument indicators was tested and proved ok.

So this may have indicated a Fault signal reaching the instrument panel.

The panel was removed and Female input plug soldered terminals re soldered. This did not sort problem.

I had a diagnostic test performed by the RAC , Even though I had no real problems starting the vehicle included with the fault list was turbo boost/ crank sensor also signal not communicating with the instrument panel.

The RPM drop out seems rather specific at 3000rpm could the turbo boost sensor causing a system fault when it kicks in via the Vacuum solenoid?

I have removed the crank sensor, and checked voltages at the 3 terminals they are as follows....

Pin 1 to pin 3 +4.98 volts (grey/violet green brown)

Pin 1 to pin 2 + 9.68 volts (Yellow violet green brown)

Pin 3 to pin 2 - 4.7 volts (grey violet yellow violet)

pin 1 appears to be the negative terminal whilst the pin 3 positive terminal which leaves pin 2 to be the signal terminal ( data extracted from Haynes Autofix)

Although it may not be the Crank sensor due to it's relative cost I have ordered a replacement and will be fitting tomorrow 12/03/26.

The next step I'm going to try is continuity between the wires in the plug to the ECU it the Crank sensor replacement doesn't work.

Any input to solving the problem would be greatly appreciated.

Regards

Just an update to the problem with the RPM fault last posted.

The crank shaft sensor was replaced and the problem was resolved.

It just goes to show that even when the car is able to run doesn't necessarily mean that the crank sensors output is not what it should be.

The only sure way is to check with an oscilloscope

This would have probably shown a low voltage square wave at its terminal output.

But for les than £20 it was worth a try..... :-)