VOLVO
ECM-1221 - Electronic throttle module signal. Faulty signal
System
Engine Control Module (ECM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsS40 (1996–2004), V40 (1996–2004)
Show models by year and engine (2)
What does this fault code mean?
The engine control module compares the actual throttle angle with the angle it has requested. If they do not agree, the code is set. The fault can lie in the relay, in the wiring to the throttle module control unit or servo, or in the throttle module itself.
Possible causes
- Contact resistance in the connections
- Faulty relay for the throttle module
- Open circuit in the signal wire to the relay control unit, or a short to supply voltage on it
- Open or short circuit to ground or supply voltage on the throttle motor signal wires
- Open circuit in the power supply or ground wire to the throttle module control unit
- Faulty throttle module
What you can do
- 1Read the codes and deal first with those for the throttle system, since they may share the same cause
- 2Check the connectors to the throttle module and the throttle position sensor for contact resistance and oxidation
- 3Have a workshop measure the resistance of the throttle motor and replace the motor if needed
- 4Checking the relay means moving relays and activating the fuel pump, so have a workshop with diagnostic equipment do it
- 5If nothing is found, an intermittent fault or a defective throttle module is likely, and a workshop should check it
Symptoms you may notice4
- Malfunction indicator lamp on
- The car performs worse
- Fuel consumption is high
- Cruise control does not work at all
What the fault can affect2
- Engine output is limited
- Cruise control is switched off
General guidance for car owners. Diagnosis on the car can point to a different cause.