After identifying the fault code, consult a repair manual specific to your Volvo 940 model for detailed troubleshooting and repair procedures. Some issues might require professional attention, especially if they involve complex systems like the engine or transmission.

After repairs, you must clear the codes manually:

Usually points to an ignition system fault, specifically with the coil or the ignition output.

Tryck på den lilla knappen i ca 1 sekund. Släpp och vänta på att LED-lampan börjar blinka.

| Code | Description | Likely Cause | | :--- | :--- | :--- | | | No Faults Found | System functioning normally. | | 1-1-2 | ECU Internal Fault | The Fuel ECU is failing. Usually requires replacement. | | 1-1-3 | Front Oxygen Sensor (O2) | Lambda sensor faulty or wiring issue. | | 1-2-1 | Mass Air Flow (MAF) Sensor | Air mass meter signal missing or out of range. | | 1-2-3 | Engine Coolant Temp Sensor | Faulty sensor affecting cold starts/fuel mix. | | 1-3-1 | RPM Sensor Signal | No signal from the flywheel sensor (Cranks but won't start). | | 1-4-3 | Front Oxygen Sensor (Lean Mix) | Vacuum leak or O2 sensor tired. | | 2-1-3 | Throttle Position Sensor (TPS) | Idle contact fault or wiring issue. | | 2-2-3 | Idle Air Control Valve (IACV) | Sticky valve or solenoid failure (causes rough idle). | | 3-1-1 | Vehicle Speed Sensor | Speedometer signal missing (transmission sensor). | | 3-2-1 | Cold Start Injector | Faulty injector or connection. |

You do not need an expensive scanner to diagnose a Volvo 940. You need a paperclip (or steady finger) and the ability to count LED flashes.

Indicates a problem with the fuel injection system, often related to the fuel pump or the fuel pump relay.