Diagnostic Aids

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Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used to diagnose the following:

Wiring harness circuits (B+, EAIR, EAIR MONITOR and ground).
Solid State Relay (SSR).
Electric Air Pump (EAP). See Fig 1.
Air injection by-pass solenoid.
Air injection diverter solenoid.
Air injection diverter valve.
Powertrain Control Module (PCM).

Fig 1: Identifying Electric AIR Pump Components

Courtesy of FORD MOTOR CO.

1) DTC P0412: Check B+ Voltage At SSR

This DTC indicates EAIR primary circuit failure. Possible causes are:
- EAIRM circuit open or short to power.
- AIR by-pass solenoid failure.
- Faulty Solid State Relay (SSR).
- Faulty PCM.
Turn ignition off. Disconnect SSR. Turn ignition on. Measure voltage between B+ terminal at SSR wiring harness connector and negative battery terminal. See Fig 2. If voltage is more 10.5 volts, go to next step. If voltage is 10.5 volts or less, go to step 6).

Fig 2: Identifying Electric AIR Test Circuit & Connector Terminals
Courtesy of FORD MOTOR CO.

2) Check EAIR Circuit Resistance

Turn ignition off. Disconnect AIR by-pass solenoid. Temporarily remove secondary air system dedicated fuse. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Measure resistance between PCM connector pin No. 70 (EAIR) and EAIR terminal at SSR wiring harness connector. If resistance is 5 ohms or more, repair open circuit. If resistance is less than 5 ohms, go to next step.

3) Check EAIR Circuit Short To Power

Measure resistance between PCM connector pins No. 70 and 71 (VPWR). Also measure resistance between PCM connector pin No. 70 and negative battery terminal. If both resistance readings are more than 10,000 ohms, go to next step. If any resistance reading is 10,000 ohms or less, repair short circuit.

4) Check For Short Circuit

Reconnect AIR by-pass solenoid connector. Measure resistance between PCM connector pins No. 70 and 71. Also measure resistance between PCM connector pin No. 70 and negative battery terminal. If both resistance readings are more than 10,000 ohms, go to next step. If any resistance reading is 10,000 ohms or less, replace AIR by-pass solenoid.

5) Check For Short Circuit

Disconnect AIR by-pass solenoid connector. Reconnect SSR connector. Measure resistance between PCM connector pins No. 70 and pins No. 51 and 103 (PWR GND). If any resistance reading is 10,000 ohms or less, replace SSR. If both resistance readings are more than 10,000 ohms, reconnect all connectors and go to step 9) (if DTC P0411 or P1411 is present) or go to step 14) (all others).

6) Check B+ Circuit Resistance

Disconnect SSR connector. Measure resistance of B+ circuit between SSR wiring harness connector and AIR system dedicated fuse. See Fig 2. If resistance is less than 5 ohms, replace dedicated fuse and go to step 8). If resistance is 5 ohms or more, repair open in B+ circuit.

7) DTC P0411

Check secondary air hoses for damage, wear or poor connections. Repair as necessary. If all hoses are okay, go to next step.

8) Check Electric Pump Operation

Disconnect air hose from AIR diverter valve(s). Start engine and allow to idle. After a 5-second delay, airflow should be present at disconnected air hose for 30-90 seconds. If airflow is present, go to step 15). If airflow is not present, go to step 11).

9) Check For Vacuum At Diverter Valve

Turn ignition off. Reconnect PCM connector. Disconnect vacuum hose from diverter valve(s). Start engine and allow to idle. After a 5-second delay, vacuum should be present at disconnected vacuum hose(s) for 30-90 seconds. If vacuum is present, go to next step. If vacuum is not present, go to step 30).

10) Check Diverter Valve

Turn ignition off. Reconnect vacuum hose at diverter valve(s). Disconnect and plug air tube from diverter valve(s) outlet side. Check diverter valve for damage and repair if necessary. Start engine and allow to idle. After a 5-second delay, vacuum should be present at disconnected air tube(s) for 30-90 seconds. If air is present from AIR diverter valve(s), repair exhaust tube(s) from diverter valve to exhaust manifold(s). If air is not present from AIR diverter valve(s), check hose from electric AIR pump to diverter valve(s). Replace as necessary. If hose is okay, replace AIR diverter valve(s).

11) Check EAIRM Circuit Voltage

Turn ignition off. Disconnect electric AIR pump. Turn ignition on. Measure voltage between EAIRM circuit at electric AIR pump wiring harness connector and chassis ground. If voltage is more than 10.5 volts for 20-30 seconds after a 5-10 second delay, go to step 13). If voltage is not as specified, go to next step.

12) Check Ground Circuit

Measure resistance between ground terminal at electric AIR pump wiring harness connector and chassis ground. If resistance is less than 5 ohms, go to step 19). If resistance is 5 ohms or more, repair open in ground circuit.

13) Check Input Air Pump Hose

Disconnect electric AIR pump air inlet hose. Check hose for water, restriction and binding. Replace hose as necessary and go to step 15). If hose is okay, go to step 15).

14) Check For Voltage At SSR

Turn ignition off. Reconnect AIR by-pass solenoid and SSR. Reconnect PCM connector. Turn ignition on. Using scan tool, select AIR and AIRM PIDs from PID/DATA monitor menu. Compare PID values. If both PID values indicate ON, replace SSR. If both PID values do not indicate ON, replace PCM.

15) Check Air Pump For Water

Turn ignition off. Disconnect electric pump air hoses and wiring harness connector. Check AIR pump for water. If water is present, replace electric pump. If water is not present proceed as follows:
- If fuse was replaced in step 6) , testing is complete.
- On all others, go to step 9).
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 15) to step 17). No test procedures have been omitted.

17) DTC P0413: Check B+ At SSR

This DTC indicates EAIRM circuit is low when electric AIR pump is commanded on. Possible causes are:
- EAIRM circuit open or short to power.
- Faulty Solid State Relay (SSR).
- Faulty electric AIR pump.
- Faulty PCM.
Turn ignition off. Disconnect SSR. Turn ignition on. Measure voltage between B+ terminal at SSR wiring harness connector and negative battery terminal. If voltage is more 10.5 volts, go to next step. If voltage is 10.5 volts or less, go to step 24).

18) Check VPWR To SSR

Turn ignition on. Measure voltage between VPWR circuit terminal at SSR wiring harness connector and chassis ground. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open circuit

19) Check EAIRM Circuit Voltage

Turn ignition off. Reconnect SSR connector. Disconnect electric AIR pump wiring harness connector. Turn ignition on. Using scan tool, access OUTPUT TEST MODE. Turn all outputs on. Using scan tool, select AIRM PID from PID/DATA monitor menu. If PID value indicates ON, remain in OUTPUT TEST MODE and go to step 23). If PID value indicates OFF and DTC P0411 is present, replace AIR pump. If PID value indicates OFF and DTC P0411 is not present, go to next step.

20) Check EAIRM Circuit For Short To Power

Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition on. Using scan tool, select AIRM PID from PID/DATA monitor menu. If PID value indicates ON, replace PCM. If PID value indicates OFF, go to next step.

21) Check EAIRM Circuit Continuity

Turn ignition off. Disconnect SSR and electric AIR pump connectors. Measure resistance between PCM connector pin No. 5 and EAIRM terminal at SSR wiring harness connector. Also measure resistance between EAIRM terminal at SSR wiring harness connector and EAIRM terminal at AIR pump wiring harness connector. If any resistance reading is 5 ohms or more, repair open in EAIRM circuit. If both resistance readings are less than 5 ohms, go to next step.

22) Check EAIRM Circuit For Short To Ground

Measure resistance between PCM connector pin No. 5 and pins No. 51 and 103. If both resistance readings are more than 10,000 ohms, replace SSR. If any resistance reading is 10,000 ohms or less, repair short to ground in EAIRM circuit.

23) Check EAIRM Circuit Voltage

Reconnect air pump. Reconnect PCM connector. Turn ignition on. Ensure scan tool is still in OUTPUT TEST MODE and all outputs on. Using scan tool, select AIRM PID from PID/DATA monitor menu. If PID value indicates ON, replace PCM. If PID value indicates OFF, repair open in EAIRM circuit.

24) Check B+ Circuit Continuity

Measure resistance of B+ circuit between B+ terminal at SSR wiring harness connector and AIR system dedicated fuse. If resistance is less than 5 ohms, replace dedicated fuse. If resistance is 5 ohms or more, repair open in B+ circuit.

25) DTC P1414: Check EAIR MONITOR Circuit Continuity

This DTC indicates electric AIR pump is commanded off, but PCM indicates AIR pump is on. Possible causes are:
- EAIRM circuit open or short to power.
- Faulty Solid State Relay (SSR).
- Faulty electric AIR pump.
- Faulty PCM.
Turn ignition off. Disconnect air pump and SSR wiring harness connectors. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Measure resistance between PCM connector pin No. 5 EAIRM terminal at electric AIR pump wiring harness connector. If resistance is 5 ohms or more, repair open in EAIRM circuit. If resistance is less than 5 ohms, go to next step.

26) Check AIR Pump Resistance

Measure resistance between electric AIR pump terminals. If resistance is .5-5.0 ohms, go to next step. If resistance is not .5-5.0 ohms, replace AIR pump.

27) Check EAIR MONITOR Circuit For Short To Power

Turn ignition on. Measure voltage between PCM connector pin No. 5 and chassis ground. If voltage is 10.5 volts or less, go to next step. If voltage is more than 10.5 volts, repair short to power.

28) Check For Voltage

Reconnect all connectors. Turn ignition on. Using scan tool, access OUTPUT TEST MODE. Turn all outputs on. Using scan tool, select AIR and AIRM PIDs from PID/DATA monitor menu. Compare PID values. If both PID values indicate ON, replace SSR. If both PID values do not indicate ON, replace PCM.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 28) to step 30). No test procedures have been omitted.

30) Check Air Pump Hoses

Turn ignition off. Remove air hose between AIR by-pass solenoid and AIR diverter valve. Check hose for restrictions, leaks and cracks. Replace hose as necessary. If hose is okay, go to next step.

31) Check AIR By-Pass Solenoid

Disconnect air by-pass solenoid connector. Turn ignition on. Using scan tool, select OUTPUT TEST MODE. Connect voltmeter to AIR by-pass solenoid wiring harness connector. Observe voltmeter while cycling outputs on and off. If voltage cycles more than .5 volt, go to next step. If voltage does not cycle more than .5 volt, go to step 33).

32) Check AIR By-Pass Solenoid Mechanical Operation

Remain in OUTPUT TEST MODE. Reconnect AIR by-pass solenoid connector. Disconnect vacuum hose from AIR by-pass solenoid. Connect vacuum hose to vacuum pump. Apply 16 in. Hg to AIR by-pass solenoid. Observe voltmeter while cycling outputs on and off. If vacuum releases as outputs cycle, repair vacuum hose between solenoid and manifold vacuum tree. If vacuum does not release, replace AIR by-pass solenoid.

33) Check Air By-Pass Solenoid Resistance

Turn ignition off. Disconnect AIR by-pass solenoid connector. Measure resistance between AIR by-pass solenoid terminals. If resistance is 50-100 ohms, go to next step. If resistance is not 50-100 ohms, replace AIR by-pass solenoid.

34) Check VPWR Circuit Voltage

Turn ignition on. Measure voltage between VPWR terminal at AIR by-pass solenoid wiring harness connector and negative battery terminal. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit.

35) Check EAIR Circuit Continuity

Turn ignition off. Disconnect SSR connector. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Measure resistance between PCM connector pin No. 70 and EAIR terminal at SSR wiring harness connector. Also measure resistance between PCM connector pin No. 70 and EAIR terminal at AIR by-pass solenoid wiring harness connector. If any resistance reading is 5 ohms or more, repair open in EAIR circuit. If both resistance readings are less than 5 ohms, go to next step.

36) Check EAIR Circuit For Short To Ground

Turn ignition off. Measure resistance between PCM connector pin No. 70 and pins No. 51 and 103. If both resistance readings are more than 10,000 ohms, go to next step. If any resistance reading is 10,000 ohms or less, repair short to ground in EAIR circuit.

37) Check EAIR Circuit For Short To Power

Measure resistance between PCM connector pins No. 70 and 71. If resistance is more than 10,000 ohms, replace PCM. If resistance is 10,000 ohms or less, repair short to power in EAIR circuit.