Circuit/System Testing
- Verify the integrity of the entire air induction system by inspecting for the following conditions:
- Any damaged components
- Loose or improper installation
- An air flow restriction
- Any vacuum leak
- Improperly routed vacuum hoses
- In cold climates, inspect for any snow or ice buildup
- Verify that restrictions do not exist in the MAP sensor port or vacuum source.
- Ignition OFF, disconnect the vacuum source at the MAP sensor. Connect the J 23738-A to the vacuum hose.
- Engine idling, verify that 15-20 in Hg of vacuum is available to the MAP sensor. If the vacuum is not within the specified range, repair the restriction in the vacuum hose to the MAP sensor.
- Ignition OFF, connect the vacuum hose to the MAP sensor. Disconnect the harness connector at the MAP sensor.
- Ignition ON, test for less than 0.2 volt between the low reference circuit terminal A and ground. If greater than the specified range, test the low reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
- Ignition OFF for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal A and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit/connections test normal, replace the ECM.
- Verify that the MAP sensor parameter is less than 12 kPa. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit/connections test normal, replace the ECM.
- Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal C. Verify that the MAP sensor parameter is greater than 102 kPa. If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
- If all circuits/connections test normal, test or replace the MAP sensor.