Diagnostic Trouble Code (DTC) Information ECM-91AC

Condition 

The engine control module (ECM) checks that the throttle follows the requested throttle angle from the engine control module (ECM). The diagnostic trouble code (DTC) is stored if a fault related to the engine or control of the engine in the throttle unit is detected.

The diagnostic trouble code (DTC) can be diagnosed when the car has been test-driven in various driving conditions.

Substitute Value 

• The cruise control is disengaged when the fault is active
• The supply to the throttle unit is switched off, causing the throttle disc to turn to the return position.

Possible Source 

Throttle jammed 

• The throttle is sticking or is blocked (e. g. dirt, icing, etc.)
• Damaged throttle unit.

Faulty signal 

• The throttle is sticking or is blocked (e. g. oil film, dust, icing)
• Damaged throttle unit
• Damaged engine control module (ECM).

Current too high 

• Short-circuit to supply voltage or ground in the wiring for the throttle unit
• Open-circuit in the wiring for the throttle unit
• Damaged throttle unit
• Damaged engine control module (ECM).

Fault symptom[s] 

• Deterioration in performance
• Uneven idle.