P38 Knock Sensor Resistance Required

Hi all,

A very slight duplication of my thread in the RR forum. Im looking for the resistance parameters on a knock sensor for a P38 V8 4.0.

The knock sensor is the early type (part number ERR5594) The sensor has been unplugged and is out of the block. If someone can give me the resistance figure so I can ascertain whether it is failed or serviceable.

I had a P0332 code come up on my OBD reader stating "Knock Sensor Fail" so I need to check it.

Thanks

They are a Piezo-Electric crystal device, and I cannot see any specification for a resistance figure in RAVE.

I've just pulled one off my spare V8 Thor engine, and it measures 5 Megohms (5,000,000 ohms)

The Bosch number is 0 261 231 140

As yours may be different, I give the information for what it is worth.

HTH

Peter

listerdiesel said:

They are a Piezo-Electric crystal device, and I cannot see any specification for a resistance figure in RAVE.

I've just pulled one off my spare V8 Thor engine, and it measures 5 Megohms (5,000,000 ohms)

The Bosch number is 0 261 231 140

As yours may be different, I give the information for what it is worth.

HTH

Peter

Click to expand...

Many thanks Peter. Is your sensor the one with the bolt that goes through the middle or is yours the one that screws directly into the block?

I dont think you will find any test data for them,its the kind of thing that LR suggest changing as a result of fault codes.I have info from LR that goes alot further than Rave and all that has is scope traces - which is how I would test them.

wyatt_erp said:

Many thanks Peter. Is your sensor the one with the bolt that goes through the middle or is yours the one that screws directly into the block?

Click to expand...

Later one that goes onto a stud in the block, Disco 2.

I don't think that there will be a big difference in the device resistance, any Piezo-Electric crystal will show a high resistance (like the old record player pickup cartridges) and will only put out a voltage when the shock waves they are tuned to occur during pinking in the engine. If both are tuned to the same peaks, they should be similar devices.

I'd guess that the old and new would be very similar.

Peter

put a scope across it and tap it...typical response should be best at 7000hz..