GM Import / GEO >> 91 Geo 1.6L

91 Geo 1.6L

Accessing Trouble Codes

To get a trouble code out of the ECM, it is necessary to jumper the BLACK wire and the BLUE/YELLOW wire at the ECM check connector, located under the hood by the battery.

Clearing Trouble Codes

  1. Clearing Stored Codes. (Long Term Memory)
    1. Turn “OFF” the ignition.
    2. Remove the tail/dome fuse for 20 seconds.
    3. Re-install fuse.
  1. Resetting the “CHECK ENGINE” light. ONLY after the maintenance service has been performed (Federal Only).
    1. Locate the cancel switch behind the access panel, below the steering column.
    2. To reset the switch, move the switch to “OFF.”

NOTE: Federal equipped vehicles have a cancel switch which needs to be reset after the 50,000, 80,000, and 100,000 mile maintenance service is completed.

Trouble Codes

89 – 92 GEO

13Oxygen Sensor circuit.
14Coolant Temperature Sensor circuit. High temperature indicated.
15Coolant Temperature Sensor circuit. Low temperature indicated.
21Throttle Position Sensor Signal Voltage High (Automatic Transmission).
22Throttle Position Sensor Signal Voltage Low.
23Intake Air temperature (MAT) Sensor. Low temperature indicated.
24Vehicle Speed Sensor circuit.
25Intake Air temperature (MAT) Sensor. High temperature indicated.
31MAP Sensor circuit – Signal Voltage Low Vacuum.
32MAP Sensor circuit – Signal Voltage High Vacuum.
33MAP Sensor circuit.
41Ignition Signal circuit.
42Crank Angle Sensor.
44Idle switch open or improper adjustment.
45Idle Switch Circuit Grounded or Improper Adjustment.
46Idle Speed Control Motor circuit.
51EGR circuit.
53Ground circuit.


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4 years ago

I’m receiving a 71 code ?