* PLEASE READ FIRST *
Note. Before performing any diagnostic test, refer to SELF-DIAGNOSTICS INTRODUCTION article for diagnostic system functions and system diagnostic procedures. For component location, see appropriate illustration in THEORY/OPERATION article.
Condition
DTC is set when ECM consistently detects more than 2 volts from VTA circuit. Possible cause is
- Throttle Position (TP) sensor.
DTC P0130 is set when sensor No. 1 voltage remains at .4 volt or more, or .6 volt or less during idle, once engine is at normal operating temperature. Possible causes are
- Heated oxygen sensor.
- Fuel trim.
DTC is set when ECM detects a response time of one second or more from sensor to change from rich to lean, or lean to rich. Possible cause is
- Oxygen sensor.
DTC is set when sensor No. 2 voltage remains at .4 volt or more, or .6 volt or less during vehicle operation (31 MPH or more), once engine is at normal operating temperature. Possible cause is
- Heated oxygen sensor.
DTC is set when either of the following conditions is present
- Sensor heater current draw exceeds 2 amps, or voltage drop of circuit exceeds 5 volt.
- Sensor heater current draw is .25 amp or less.
Possible causes are
- Heated oxygen sensor open or short circuit.
- Heated oxygen sensor heater.
- ECM.
- Fuel line pressure.
- Injector blockage or leak.
- Heated oxygen sensor.
- Manifold Absolute Pressure (MAP) sensor.
- Engine Coolant Temperature (ECT) sensor.
DTCS P0301-P0304: CYLINDERS NO. 1-4 MISFIRE DETECTED
Note. When 2 or more codes for a misfiring cylinder are recorded repeatedly, but DTC P0300 is not recorded, it indicates that misfires were detected and stored into ECM memory at different times.
Two conditions can cause code to set. These are
- During any particular 200 revolutions of engine, misfiring is detected which can cause catalytic converter overheating and/or damage.
- During any particular 1000 revolutions of engine, misfiring is detected which can cause a deterioration in emission levels.
For possible causes, see DTC P0300 : RANDOM MISFIRE DETECTED test.