Manifold Absolute Pressure Sensor/Intake Air Temperature Sensor, Checking
Manifold Absolute Pressure Sensor/Intake Air Temperature Sensor, Checking
The following procedure is used to diagnose the Manifold Absolute Pressure (MAP) Sensor (G71) and Intake Air Temperature (IAT) Sensor (G42) which is controlled by Engine Control Module (J623).
• The Intake Air Temperature (IAT) Sensor (G42) is part of the Manifold Absolute Pressure (MAP) Sensor (G71) and cannot be replaced separately
• Use only gold-plated terminals when servicing terminals in harness connector of Manifold Absolute Pressure (MAP) Sensor (G71) / Intake Air Temperature (IAT) Sensor (G42).
Special tools, testers and auxiliary items required
• multimeter.
• Wiring diagram.
Test requirements
• The Engine Control Module (ECM) (J623) fuse OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position "P" or "N".
• A/C switched off.
• Ground (GND) connections between engine/transmission/chassis OK.
• Coolant Temperature at least 80° C.
• Ignition switched off.
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.
Start diagnosis
- Connect the scan tool.
- Using the scan tool, Check the temperature of the Intake Air Temperature (IAT) Sensor (G42) at idle:
- Remove the engine covers. Refer to the appropriate service manual.
- Start engine and let idle.
- Switch the ignition OFF.
If the specified value was obtained:
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
- Go to Final procedures
If any of the specified value was Not obtained:
- Disconnect the Manifold Absolute Pressure (MAP) Sensor (G71) Intake Air Temperature (IAT) Sensor (G42) electrical harness connector - 1 -.
- Switch the ignition ON.
- Using a Multimeter, check the Manifold Absolute Pressure (MAP) Sensor (G71) Intake Air Temperature (IAT) Sensor (G42) electrical harness connector terminals 1 to 3 for voltage.
Specified value: near 5.0 V
- Switch the ignition OFF.
- Continue test according to the following table:
Checking wiring
- Remove the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.
- Using a Multimeter, Check the Manifold Absolute Pressure (MAP) Sensor (G71) Intake Air Temperature (IAT) Sensor (G42) electrical harness connector to the Motronic Engine Control Module (ECM) electrical harness connector T60 for an open circuit.
Specified value: 1.5 ohms Max.
If the specified values were Not obtained:
- Check the wiring connection for an open circuit, short circuit to Battery voltage or Ground
- Check the wiring connection for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
- Go to Final procedures
If the specified values were obtained:
- If no faults were found Replace the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.
- Go to Final procedures
Component Check
- Remove the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.
- Using a Multimeter, Check the Manifold Absolute Pressure (MAP) Sensor (G71) Intake Air Temperature (IAT) Sensor (G42) electrical harness connector to the Motronic Engine Control Module (ECM) electrical harness connector T60 for an open circuit.
Specified value: 1.5 ohms Max.
If the specified values were Not obtained:
- Check the wiring connection for an open circuit, short circuit to Battery voltage or Ground
- Check the wiring connection for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
- Go to Final procedures
If the specified values were obtained:
- Replace the Manifold Absolute Pressure (MAP) Sensor (G71) Intake Air Temperature (IAT) Sensor (G42). Refer to appropriate service manual.
Final procedures
- Reinstall the engine cover with air filter, if necessary. Refer to the appropriate service manual.
- After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Programming and Relearning.