FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Diagnostic Trouble Code (DTC) Information






Diagnostic trouble code (DTC) information

Condition
If the Engine control module (ECM) registers that the idle speed is higher than 200 rpm or lower than 100 rpm, from the normal idle speed, for a longer time than 10 seconds despite the idle control being active and attempting to control the speed to normal speed, then diagnostic trouble code ECM-990A, Faulty rpm, is generated.

Substitute value
none

Possible source
- This fault has probably occurred in the fuel injection system and the diagnostic trouble code (DTC) never occurs on its own.
Look for the cause of the fault in another part of the system.

Fault symptom[s]
- Driving/Poor performance/lacks power
- Idling/Uneven idle
- Driving/Engine stalls/During acceleration
- Driving/Engine stalls/During deceleration
- Cruise control/Does not engage
- Text window and warning symbol/Red symbol and text message