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:

CIRCUIT PIN IDENTIFICATION

NOTE: For diagnosis of DTC P1105, go to step 15).

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 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 may be intermittent. See TEST Z for intermittent diagnostics.

4) Check MAP/BARO Sensor Circuit For Short To Ground

Turn ignition off. Disconnect PCM. Measure resistance between PCM connector MAP/BARO terminal No. 41 (Pink wire) and ground. See Fig 1. Also see CIRCUIT PIN IDENTIFICATION table. If resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short to ground. Restore electrical connections and repeat QUICK TEST .

5) Check MAP/BARO Circuit For Short To Power

Turn ignition off. Disconnect PCM. Measure resistance between PCM connector MAP/BARO terminal No. 41 (Pink wire) and VPWR circuit terminals No. 66, 71 and 97 (Black/White wires). If resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short to power in MAP/BARO circuit. Restore electrical connections and repeat QUICK TEST .

6) Check VREF Circuit

Turn ignition on. Ensure PCM is connected. Measure voltage between VREF pin (Brown wire) at MAP/BARO sensor harness connector and chassis 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 in VREF circuit (Brown wire). Restore electrical connections and repeat QUICK TEST .

7) Check For Open SIG RTN Circuit

Turn ignition off. Disconnect PCM. Measure resistance of SIG RTN circuit (Blue wire) between MAP/BARO sensor harness connector and PCM connector terminal No. 41. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open SIG RTN circuit (Blue wire). Restore electrical connections and repeat QUICK TEST .

8) Check SIG RTN Circuit For Short To Ground

Turn ignition off. Disconnect PCM. Measure resistance of SIG RTN circuit (Blue wire) 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 to ground. Restore electrical connections and repeat QUICK TEST .

9) Check SIG RTN Circuit For Short To Power

Turn ignition off. Disconnect PCM. Measure resistance between SIG RTN circuit terminal No. 58 (Blue wire) and VPWR circuit terminals No. 66, 71 and 97 (Black/White wires). If resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short to power in SIG RTN circuit. Restore electrical connections and repeat QUICK TEST .

10) Check MAP/BARO Sensor Function

Turn ignition off. Connect NGS tester to fuse panel DLC. Warm engine to operating temperature. Ensure MAP/BARO sensor is connected. Disconnect MAP/BARO sensor vacuum line. Turn ignition on. 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. Restore electrical connections and repeat QUICK TEST .
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

DTC P0115 indicates fault in MAP/BARO solenoid. Possible causes are circuit open or shorted to ground, vacuum hoses open or restricted, faulty MAP/BARO solenoid, or faulty MAP/BARO sensor. Turn ignition off. Remove vacuum lines from MAP/BARO sensor and solenoid. Inspect vacuum lines for restrictions or leaks. Replace as necessary. If vacuum lines are okay, go to next step.

16) Check MAP/BARO Solenoid IGN Circuit

Turn ignition off. Disconnect MAP/BARO solenoid harness connector. Turn ignition on. Measure voltage between Blue/Yellow wire at MAP/BARO solenoid harness connector and ground. If battery voltage exists, go to next step. If battery voltage does not exist, repair open Blue/Yellow wire. Restore electrical connections and repeat QUICK TEST .

17) Check MAP/BARO Circuit For Short To Ground

Turn ignition off. Disconnect MAP/BARO solenoid harness connector. Disconnect PCM. Measure resistance between Pink wire at MAP/BARO solenoid harness connector and chassis 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 in MAP/BARO circuit (Pink wire). Restore electrical connections and repeat QUICK TEST .

18) Check For Open MAP/BARO Solenoid Circuit

Turn ignition off. Disconnect PCM. Measure resistance of MAP/BARO solenoid circuit between MAP/BARO solenoid connector and PCM connector terminal No. 38 (Purple wire). If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open MAP/BARO solenoid circuit (Purple wire). Restore electrical connections and repeat QUICK TEST .

19) Check For Open MAP/BARO Solenoid

Turn ignition off. 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. Restore electrical connections and repeat QUICK TEST .

Fig 2: Testing MAP/BARO Solenoid

Courtesy of FORD MOTOR CO.