VOLVO
ECM-902B - Communication with throttle unit. Signal too high
System
Engine Control Module (ECM)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
7 modelsC70 Cabriolet (1998–2005), C70 Coupé (1998–2002), S60 (2001–2009), S70 (1997–2000), S80 (1999–2006), V70 (1997–2000), V70 (2000–2008)
Show models by year and engine (20)
- Volvo C70 Cabriolet (1998–2005)2000Engine B5244S only
- Volvo C70 Coupé (1998–2002)1999Engine B5254S DENSO only
- Volvo C70 Coupé (1998–2002)2000Engine B5244S only
- Volvo S60 (2001–2009)2001Engine B5244S, B5244S2 only
- Volvo S60 (2001–2009)2002Engine B5244S, B5244S2, B5244SG, B5244SG2 only
- Volvo S60 (2001–2009)2003–2005Engine B5244SG, B5244SG2 only
- Volvo S60 (2001–2009)2006–2008Engine B5244SG only
- Volvo S70 (1997–2000)1999Engine B5254S DENSO only
- Volvo S70 (1997–2000)2000Engine B5244S, B5244S2, B5244SG, B5244SG2 only
- Volvo S80 (1999–2006)2000Engine B5244S, B5244S2 only
- Volvo S80 (1999–2006)2001Engine B5244S, B5244S2, B5244SG only
- Volvo S80 (1999–2006)2002Engine B5244S, B5244S2, B5244SG, B5244SG2 only
- Volvo S80 (1999–2006)2003–2005Engine B5244SG, B5244SG2 only
- Volvo S80 (1999–2006)2006Engine B5244SG only
- Volvo V70 (1997–2000)1999Engine B5254S DENSO only
- Volvo V70 (1997–2000)2000Engine B5244S, B5244S2, B5244SG, B5244SG2 only
- Volvo V70 (2000–2008)2001Engine B5244S, B5244S2, B5244SG only
- Volvo V70 (2000–2008)2002Engine B5244S, B5244S2, B5244SG, B5244SG2 only
- Volvo V70 (2000–2008)2003–2005Engine B5244SG, B5244SG2 only
- Volvo V70 (2000–2008)2006–2008Engine B5244SG only
What does this fault code mean?
The ECM has not received any CAN signal from the throttle module after start, even though the engine runs at a sufficiently high speed. This variant therefore concerns communication after start. The code can be set together with other codes, which should then be read out at the same time.
Possible causes
- Delayed engagement of the system relay when the ignition is switched on
- The voltage supply to the throttle module is too high when the ignition is switched on
- Interference on the CAN wiring
- Defective CAN wiring
- A damaged control module in the CAN network
What you can do
- 1Check that the system relay engages in time at start and that the throttle module gets the correct voltage, since a delayed engagement can cause this code
- 2Check the CAN wiring for damage and measure that it has no break or short to ground or voltage
- 3Check the CAN connectors for contact resistance and oxidation
- 4Read the CAN codes in the other control modules first and trace them; the reconfiguration does not show the root cause
- 5If you have diagnostic equipment, read the throttle signals in live data during start-up and a road test and see whether they drop out
- 6If the fault remains, have a workshop check the control modules in the CAN network
Symptoms you may notice5
- The accelerator pedal is ignored when braking
- Cruise control cannot be engaged
- Uneven idle
- Jerking during engine braking
- The electronic throttle system warning lamp is on for the C70 and for the S/V70 up to the year 2000
What the fault can affect3
- The throttle and accelerator pedal behave as if they were mechanically linked
- Fuel cut-off always follows the pedal position during the reconfiguration
- Cruise control is switched off during the driving cycle in which the fault was detected, and it returns at the next start if the fault has gone
General guidance for car owners. Diagnosis on the car can point to a different cause.