Diagnostic Aids
Perform this test only when directed by QUICK TEST or other test.
This test is intended to diagnose the following components and circuits:
- Manifold Absolute Pressure/Barometer (MAP/BARO) sensor.
- MAP/BARO solenoid.
- PCM.
- Harness circuits; MAP/BARO.
CIRCUIT PIN IDENTIFICATION
| Circuit | PCM Pin No. | Wire Color |
|---|---|---|
| MAP/BARO | 41 | Pink |
| VREF | 57 | Brown |
| SIG RTN | 58 | Blue |
| MAP/BARO Sol. | 33 | Violet |
NOTE:
For diagnosis of DTC P1105, go to step 15).
- 1) Check MAP/BARO Sensor - BARO Reading
Disconnect vacuum line to MAP/BARO sensor and solenoid. Check for restrictions and leaks. Repair as necessary. Connect NGS tester to DLC. Turn ignition on. Using scan tool, access MAP/BP_V PID. If reading is greater than 2.6 volts, go to next step. If reading is not greater than 2.6 volts, go to step 4). - 2) Check MAP/BARO Sensor
Disconnect vacuum line to MAP/BARO sensor. Connect vacuum pump to MAP/BARO sensor inlet. Apply 2.99 in. Hg of vacuum to MAP/BARO sensor. Access MAP/BP_V PID. If PID reads greater than 2.6 volts, go to next step. If PID reads less than 2.6 volts, fault is intermittent. - 3) Check For Open MAP/BARO Circuit
Turn ignition off. Disconnect MAP/BARO sensor harness connector. Disconnect PCM harness connector. Measure resistance of MAP/BARO circuit between MAP/BARO sensor connector and PCM harness connector terminal No. 41. See Figure and Fig 1 . See CIRCUIT PIN IDENTIFICATION table. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open in circuit. - 4) Check MAP/BARO Sensor Circuit For Short To Ground
Turn ignition off. Disconnect PCM and MAP/BARO sensor harness connectors. Measure resistance between PCM connector MAP/BARO terminal No. 41 and ground. If resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short to ground. - 5) Check MAP/BARO Circuit For Short To Power
Turn ignition off. Measure resistance between MAP/BARO and PCM VPWR circuits at PCM harness connector. See Figure. If resistance is greater than 10 k/ohms, go to next step. If resistance is not greater than 10 k/ohms, repair short to power in circuit. - 6) Check VREF Circuit
Reconnect PCM harness connector. Turn ignition on. Measure voltage between MAP/BARO sensor harness connector VREF circuit and ground. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, repair open or short to ground in VREF circuit. - 7) Check For Open SIG RTN Circuit
Turn ignition off. Disconnect PCM harness connector. Measure resistance of SIG RTN circuit between MAP/BARO sensor harness connector and PCM harness connector terminal No. 58. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open in SIG RTN circuit. - 8) Check SIG RTN Circuit For Short To Ground
Measure resistance of SIG RTN circuit between MAP/BARO sensor harness connector and ground. If resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short in circuit. - 9) Check SIG RTN Circuit For Short To Power
Measure resistance between SIG RTN circuit terminal No. 58 (Blue wire) and VPWR circuit terminals No. 66, 71 and 97 (Black/White wires) at PCM. If resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short in SIG RTN circuit. - 10) Check MAP/BARO Sensor Function
Connect New Generation Star (NGS) tester to DLC. Ensure engine is at normal operating temperature. Ensure MAP/BARO sensor and PCM connectors are connected. Disconnect MAP/BARO sensor vacuum line. Turn ignition on, with engine off. Using NGS tester, access MAP/BP_V PID. If MAP/BP_V PID reading is 3.2-4.8 volts, replace PCM. If MAP/BP_V PID reading is not 3.2-4.8 volts, replace MAP/BARO sensor.NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 10) to step 15) . No test procedures have been omitted. - 15) Check MAP/BARO Vacuum Line
Turn ignition off. Disconnect vacuum lines from MAP/BARO sensor and solenoid. Inspect vacuum lines for restrictions or leaks. Repair or replace as necessary. If vacuum lines are okay, go to next step. - 16) Check MAP/BARO Solenoid IGN Circuit
Disconnect MAP/BARO solenoid harness connector. Turn ignition on. Measure voltage at IGN circuit between MAP/BARO solenoid harness connector and ground. If voltage is greater than 10 volts, go to next step. If voltage is not greater than 10 volts, repair open in circuit. - 17) Check MAP/BARO Circuit For Short To Ground
Turn ignition off. Disconnect MAP/BARO solenoid harness connector. Disconnect PCM harness connector. Measure resistance between MAP/BARO solenoid circuit at MAP/BARO solenoid harness connector (Pink wire) and chassis ground. If resistance is greater than 10 k/ohms, go to next step. If resistance is not greater than 10 k/ohms, repair short in circuit. - 18) Check For Open MAP/BARO Solenoid Circuit
Measure resistance of MAP/BARO solenoid circuit between MAP/BARO solenoid connector and PCM connector. See WIRING DIAGRAMS article. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, repair open in MAP/BARO solenoid circuit. - 19) Check For Open MAP/BARO Solenoid
Remove MAP/BARO solenoid. Using jumper wires, apply battery power and ground to solenoid (ensure polarity is correct). Blow air into port "A" of MAP/BARO solenoid. There should be air passage between ports "A" and "C", and no air passage between ports "A" and "B". Remove power from solenoid. Blow air into port "A". There should be no air passage between ports "A"and "C", and air passage between ports "A" and "B". See Fig 2. Replace solenoid if operation is not as specified. If solenoid operates as specified, replace PCM.