This is a re-post with different subject line (one posted yesterday may have been a little unclear)

My 1991 940 (252,000 miles) engine has an occassional stumble (tach does not drop) while driving and today stalled while coming to a stop. OBD connector 2 code is 121 (according to FAQ is AMM), and code 224 on connector 6. According to FAQ there is no 224 code for Bosch/LH2.4. Would appreciate insight into the 224 code.

Checking my gas milage on last fillup, was only 14MPG driving around town. I guess AMM would explain this.

This car has new RPM sensor, new F1 relay, new knock sensor, recent FPR, recent IAC, recent main fuel pump and recent power stage. AMM is original.

Thanks for any info/suggestions.

Gary

Is your car a turbo or NA? Are all NA 700/900 cars in 1991 Rex/Regina?

If your car is Rex/Regina the 224 code is "Engine temperature sensor signal absent or faulty"

From the GreenBook "If the signal from the enine temperature sensor corresponds to a temperatrue below -40F or above 250F the fault code is set. The control unit then assumes an engine temperature of approximately 194F so that the car can still be driven"

Causes are listed a break or short to ground in lines, connection resistance in connectors, poor ground at chassis, or break/short circuit to ground in sensor.

Again if the car is Rex/Regina the 121 code is Pressure sensor signal absent or faulty. GreenBook says "If the siganl has an abnormally high or low value, the fault code is set. If the signal from the pressure sensor is missing the control unit compensates with fixed values (limp home mode) so that the car can be driven.

Causes: Breakage or short circuit to ground in wires, connections of pressure sensor. Connector resistance in connections. Poor chassis connection of signal ground.

Symptom: Poor acceleration, the engine cuts out at idling speed, difficulty in starting when hot or cold.

But of course if you have a turbo all this means nothing :-)

Randy

Thanks for your time and info Randy. It is a turbo and as I mentioned, it is a Bosch LH2.4 (non-Regina). Regina information you mentioned is in the FAQ section (including 224 code), but no 224 code is listed for Bosch LH2.4 system. As Mark mentioned, it sounds like I have a bogus code.\

Thanks again,

Gary

Every now and then I get a code that is not in the book too. I can find no reference anywhere to 224, double check it and make sure that is what it is.

Mark

Thanks Mark. I triple checked and is 224. Nice to know I'm not the only when with a bogus code. I'm going to check AMM connections and resistance reading and if find nothing I'll start by replacing it.

Thanks again,

Gary