Start problem Model 740 Year 1989

Check the radio supressor relay at the right front wheel well. But if it was running on one cylinder sounds more like the ECU is bad.

Have you checked for codes on all checkbox (OBD) pins? IIRC There are at least two pins to check on your model (2 & 6).

Cheers, Peter.

I did not know about the "pin 2" option. Anyhow, I checked and the error code is following:

3-1-2 2-3-1 1-1-3 Do you know what the codes indicated and where (generally) are the codes listed? The "pin 6" codes remains all three (3); 1-1-1 thanks - Ulf

I checked and found the relay "hanging" on its cables loose by the front weel weel. The bracket/holder seems to be lost. How should it look like? I will purchase a "new" relay tomorrow by Volvo. The realy is most likely bad after vibrations etc.. How can I find out? Short circuit, so the fuel pump gets power? However, I checked the ECU error codes with pin 2 connection and found following:

3-1-2 2-3-1 1-1-3 The pin 6 showes: 1-1-1. do you know anything about the codes? Thanks - Ulf

Go here:

Ulf - the codes are listed over here:

I suspect you have a fuel injector problem.

Pin 6 showing 1-1-1 means there is no ignition system fault. Pin 2 showing 3-1-2 means no knock sensor output, 2-3-1 means fuel supply too rich or too weak in part-load stage and 1-1-3 means fuel supply too rich/weak. This latter code backs up the previous code the main fault being the lack of signal from the knock sensor. This is to be found about halfway along the left hand side of the engine just below the head-block joint. It has a screened cable to feed it's signal to the ECU which may have become detatched from it's connector to the wiring loom. Make sure that the connector is OK and in good contact then reset the OBD codes The codes are found in the Haynes 940 manual sections 4A (Fuel) and 5B (Ignition), as is the reset information. The relevant information is also to be found in the Chilton manuals C72300 and C72302, both available from Haynes publishing on

where they do mail order. Cheers, Peter.

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Thank you for your information. Today is Monday and I was this morning in contact with Volvo here in Luxembourg. They claim the engine should start even if the "knock sensor" is malfunctioning. It must be something else. I have done following today (and yesterday):

1 - take the "radio relay" apart and checked, (very clean inside) works fine.

2 - take the "fuel injection relay" apart and checked, (very clean inside), works fine.

3 - checked the cable connector to the "knock sensor" and cleaned.

4 ? Total ?power off? (disconnected the battery).

Next I checked the error codes:

pin 6: 1-1-1 (3 times)

pin 2: 1-1-1 (3 times)

I attempted to start the engine. Still did not ignite. Note: I could smell gasoline (so the pump etc. appears to functioning).

Again I checked the error code:

pin 6: 1-1-1 (3 times)

pin 2: 3-1-2 (3 times)

Volvo does not have any parts in stock. They have to order from U.K. and I should have a new ?knock sensor? tomorrow. But I need the car today and as said the ?knock sensor? should not make the car refuse to start.

Anybody have an idea what is going on?

Now the problem is solved. A neighbour told me he basically have had the same problem last year. Squirrels are during the night eating the cables. I checked the ignition cables and they had a lot of tooth marks. After taking away the plugs and clean out a "wet" engine, replacing two cables (to the radio relay and the ignition coil) looking "suspicious" (plus the ignition cables), the car started up fine. Next week when I am back from Germany, I will check the "knock sensor" etc..

So now the "knock sensor" has been exchanged and no error message. Also, I have installed an ultra sonic device recommended by my neighbour (giving a

12 KHz/85 dB sound), to keep the Squirrels away (and rats). However, more problems, when in Germany, I recognized that the fuel consumption was much higher then previously. I checked for error codes and got following:

2-2-1: Fuel trim (lambda control) too lean at part load; Lean; air leak; low fuel pressure; bad AMM

1-1-3: Fuel trim (lambda control) too lean or rich; Mixture incorrect; O2S wiring fault

2-1-3: Throttle switch full load setting faulty or grounding short; Wiring fault to TPS or TPS failure

I will check the AMM and the O2 (Oxygen Sensor) as well as the TPS. BUT why do I get all these sensor errors?