Diagnostic trouble code (DTC) information ECM-91A7

Condition

Fig 1: Identifying Damper Motor Integrated With Electronic Unit

Courtesy of VOLVO CARS OF NORTH AMERICA.

Turbo engines

If Electronic throttle module (ETM) registers a too high difference between desired value and current value in the internal regulator or a too high current passes through the electronic throttle module's torque motor, then this information is sent to Engine control module (ECM), which then stores diagnostic trouble code ECM-91A7, Faulty control.

5-cylnder non-turbo engines

If Electronic throttle module (ETM) registers a too high difference between desired value and current value in the internal regulator, a too high current passes through the electronic throttle module's torque motor, or that the throttle disc does not move despite a control signal to the motor, then this information is sent to Engine control module (ECM), which then stores diagnostic trouble code ECM-91A7, Faulty control.

For more information about the electronic throttle system and related components such as the electronic throttle module, accelerator pedal position sensor, brake light switch, clutch pedal position sensor, and brake pedal position sensor:Design Function

Substitute Value

Fuel cut-off that follows accelerator pedal position.

Engine speed is regulated via fuel cut-off by deactivating the injectors one at a time. Engine speed is determined by gas pedal position sensor position and engine speed is maximized to about 5000 RPM. This reconfiguration can cause the engine to idle very unevenly since the engine control module (ECM) regulates engine speed by cutting of the fuel to the cylinders individually. Do not confuse this reconfiguration (engine behavior) with an actual driveability problem that was present before reconfiguration.

Closing of throttle during braking.

The accelerator pedal position is ignored when the brake pedal is depressed.

Cruise control off.

Cruise control off during entire operating cycle in which fault was detected. If the fault is no longer present, the function is available the next time the car is started.

Throttle switched off (only 5-cylinder aspiration engines).

The electronic throttle module (ETC) deactivates the throttle motor control, which means that the throttle is not actuated and assumes its mechanical stop position. This means about 20% throttle opening. This reconfiguration is always followed by fuel cut-off.

For upgraded software, released in 2006 or later, adjustments have been made to substitute values. In driving cycles when the fault is active, fuel shut-off that follows the accelerator pedal position will be activated.

See Identifying upgraded software ECM/ETM

Possible Source

something is blocking the throttle position sensor (an oil film, dust etc.)
poorly charged battery or corroded in the connecting cables
the power supply to the throttle unit
defective throttle unit.

This diagnostic trouble code is generated in combination with other trouble codes. Information on the possible root cause is described.
See Information about combined diagnostic trouble codes (DTCs)

Fault symptom[s]

the accelerator pedal (AP) is ignored when braking
the cruise control cannot be activated
uneven idle
jerks during engine braking
very poor throttle response (only 5 cylinder engines with DENSO electronics)
maximum speed approximately 50 km/h (only 5 cylinder engines with DENSO electronics)
the ETS warning lamp lights (C70 and S/V70 -2000 only).