| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
MAP sensor detects manifold pressure as a voltage that is supplied to the ECM to determine basic injection duration and advance angle. DTC is set when ECM detects an open or short in MAP circuit. ECM will operate in fail-safe mode if DTC P0105 is set. Possible causes are
- Open or short in MAP sensor circuit.
- MAP sensor.
- ECM.
Scheme 45
- Connect scan tool to DLC No. 3 connector. (Scheme 45) Turn ignition on. Using scan tool, read MAP sensor value. If reading is same as atmospheric pressure, go to next step. If reading in not same as atmospheric pressure, check component and ECM connections. Problem is intermittent.
- Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 9 (Brown wire) and No. 11 (Light Green/Red wire) at ECM E6 connector. (Scheme 46) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
- Backprobing ECM connector, measure voltage between terminals No. 2 (Pink wire) and No. 11 (Brown wire) at ECM E6 connector. If voltage is 3.3-3.9 volts, replace ECM. If voltage is not 3.3-3.9 volts, go to next step.
- Check for open or short circuit in wiring harness between MAP sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace MAP sensor.
