Code 1302

SYSTEM DESCRIPTION
This system allows the absolute pressure sensor to monitor either ambient barometric pressure or intake manifold pressure. The MAP/BARO switch solenoid valve switches between two passages by ON-OFF pulse signals from the ECM. (One passage is from the intake air duct, the other is from the intake manifold.) Either ambient barometric pressure or intake manifold pressure is applied to the absolute pressure sensor.

COMPONENT DESCRIPTION
The MAP/BARO switch solenoid valve switches its air flow passage according to the voltage signal sent from the ECM. When voltage is supplied from the ECM, the MAP/BARO switch solenoid turns "ON". Then, the absolute pressure sensor can monitor the ambient barometric pressure. When voltage is not supplied from the ECM, the MAP/BARO switch solenoid valve turns "OFF". Then, the sensor monitors intake manifold pressure.

CONSULT Reference Value in Data Monitor Mode
Specification data are reference values.

ECM Terminals and Reference Value
Specification data are reference values and are measured between each terminal and 43 (ECM ground).

ON BOARD DIAGNOSIS LOGIC

DTC CONFIRMATION PROCEDURE
Perform "Procedure for malfunction A" first. If the 1st trip DTC cannot be confirmed, perform "Procedure for malfunction B".

NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.

PROCEDURE FOR MALFUNCTION A

TESTING CONDITION: Before performing the following procedure, confirm that battery voltage is more than 11 V at ignition switch "ON".

With CONSULT
1. Turn ignition switch "ON" and select "DATA MONITOR" mode with CONSULT.
2. Wait at least 10 seconds.
3. If 1st trip DTC is detected, go to "Diagnostic Procedure".

With GST
1. Turn ignition switch "ON" and wait at least 10 seconds.
2. Select "MODE 7" with GST.
3. If 1st trip DTC is detected, go to "Diagnostic Procedure".

Without Scan Tools
1. Turn ignition switch "ON" and wait at least 10 seconds.
2. Turn ignition switch "OFF", wait at least 5 seconds and then turn "ON".
3. Perform "Diagnostic Test Mode II (Self-diagnostic results)" with ECM.
4. If 1st trip DTC is detected, go to "Diagnostic Procedure".

PROCEDURE FOR MALFUNCTION B

TESTING CONDITION: Always perform at a temperature above 5 °C (41 °F).

With CONSULT
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds.
3. Turn ignition switch "ON" again and select "DATA MONITOR" mode with CONSULT.
4. Make sure that "TANK/F/TEMP SE" is more than 0 °C (32 °F).
5. Start engine and let it idle for at least 10 seconds.
6. If 1st trip DTC is detected, go to "Diagnostic Procedure".

With GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds.
3. Turn ignition switch "ON".
4. Check that voltage between ECM terminal 63 and ground is less than 4.2 V.
5. Start engine and let it idle for at least 10 seconds.
6. Select "MODE 7" with GST.
7. If 1st trip DTC is detected, go to "Diagnostic Procedure".

Without Scan Tools
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds.
3. Turn ignition switch "ON".
4. Check that voltage between ECM terminal 63 and ground is less than 4.2 V.
5. Start engine and let it idle for at least 10 seconds.
6. Turn ignition switch "OFF", wait at least 5 seconds and then turn "ON".
7. Perform "Diagnostic Test Mode II (Self-diagnostic results)" with ECM.
8. If 1st trip DTC is detected, go to "Diagnostic Procedure".

WIRING DIAGRAM

DIAGNOSTIC PROCEDURE
If the trouble is duplicated after "PROCEDURE FOR MALFUNCTION A", perform "PROCEDURE A" below. If the trouble is duplicated after "PROCEDURE FOR MALFUNCTION B", perform "PROCEDURE B".

1 CHECK POWER SUPPLY:

2 DETECT MALFUNCTIONING PART:

3 CHECK OUTPUT SIGNAL CIRCUIT:

4 DETECT MALFUNCTIONING PART:

5 CHECK MAP/BARO SWITCH SOLENOID VALVE:

6 CHECK INTERMITTENT INCIDENT:

PROCEDURE A

1 INSPECTION START:

2 CHECK VACUUM SOURCE TO MAP/BARO SWITCH SOLENOID VALVE AND CIRCUIT:

3 CHECK VACUUM SOURCE TO ABSOLUTE PRESSURE SENSOR:

4 CHECK VACUUM HOSE:

5 CHECK VACUUM PORT:

6 CHECK POWER SUPPLY:

7 DETECT MALFUNCTIONING PART:

8 CHECK OUTPUT SIGNAL CIRCUIT:

9 DETECT MALFUNCTIONING PART:

10 CHECK MAP/BARO SWITCH SOLENOID VALVE:

11 CHECK INTAKE SYSTEM:

12 CHECK HOSE BETWEEN ABSOLUTE PRESSURE SENSOR AND MAP/BARO SWITCH SOLENOID VALVE:

13 CHECK HARNESS CONNECTOR:

14 CHECK ABSOLUTE PRESSURE SENSOR:

15 CHECK INTERMITTENT INCIDENT:

PROCEDURE B

COMPONENT INSPECTION

With CONSULT
1. Start engine and warm it up to normal operating temperature.
2. Perform "MAP/BARO SW/V" in "ACTIVE TEST" mode with CONSULT.

3. Check the following.
- Condition: At idle under no-load
- CONSULT display
- Time for voltage to change
4. If NG, check solenoid valve as shown below.

Without CONSULT
1. Turn ignition switch "OFF" and remove MAP/789BARO switch solenoid valve.

2. Check air passage continuity.
3. Check the time required for the solenoid valve to switch. It should be less than 1 second.
4. If NG, replace solenoid valve.