Diagnostic Aids

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 (AIRB, B+, EAIR, EAIR MONITOR & GND)
• Solid State Relay (SSR)
• Electric Secondary Air Injection (AIR) Pump. See Fig 1.
• Secondary Air Injection (AIR) By-Pass Solenoid
• Powertrain Control Module (PCM)
• Secondary Air Injection (AIR) Diverter Valve
• Vacuum Supply & Hoses
• Air Silencer
• Secondary Air Injection (AIR) Check Valve
• Partial Restricted Exhaust

Fig 1: Identifying Electric AIR Pump Components

Courtesy of FORD MOTOR CO.

1. 1) DTC P0412: Check B+ Voltage To Solid State Relay
   
   DTC P0412 indicates secondary air injection system AIR circuit failure. Possible causes are:
   • AIR Circuit Open Or Short To VPWR
   • AIR By-Pass Solenoid Fault
   • Faulty PCM
   • Faulty Solid State Relay (SSR)
   • Faulty AIR Pump

   Turn ignition switch to OFF position. Disconnect SSR harness connector. Turn ignition switch to ON position. Using a DVOM, measure voltage of B+ circuit between SSR harness connector and negative battery terminal. See Fig 2. If voltage is more than 10.5 volts, supplied voltage is okay. 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. 2) Check EAIR Circuit Resistance
   
   Turn ignition switch to OFF position. Disconnect AIR by-pass solenoid. Temporarily remove secondary air injection system dedicated fuse. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of EAIR circuit between PCM harness connector, SSR harness connector and secondary air injection by-pass solenoid harness connector. See Fig 2. If either resistance measurement is 5 ohms or more, repair open in affected circuit. If both resistance measurements are less than 5 ohms, go to next step.
3. 3) Check EAIR Circuit For Short To PWR Or GND With Air By-Pass Solenoid Disconnected
   
   Using a DVOM, measure resistance between PCM harness connector EAIR and VPWR circuit terminals. See Fig 2. Using a DVOM, measure resistance between negative battery terminal and PCM harness connector EAIR terminal. If both resistance measurements are more than 10 k/ohms, go to next step. If either resistance measurement is 10 k/ohms or less, repair short between affected circuits.
4. 4) Check Air By-Pass Solenoid Resistance
   
   Ensure AIR by-pass solenoid is disconnected. Using a DVOM, measure resistance between both AIR by-pass solenoid connector terminals. If resistance measurement is 50-100 ohms, go to next step. If resistance measurement is not 50-100 ohms, replace AIR by-pass solenoid.
5. 5) Check EAIR Circuit For Short To PWR Or GND With SSR Connected
   
   Ensure AIR by-pass solenoid is disconnected. Reconnect SSR harness connector. Using a DVOM, measure resistance between PCM harness connector EAIR, PWR GND and VPWR circuit terminals. See WIRING DIAGRAMS article. See Figure and Fig 2 . If any resistance measurement is 10 k/ohms or less, replace SSR. If all resistance measurements are more than 10 k/ohms, reconnect all connectors and go to step  9) for DTC P0411, or go to step  16) for all others.
6. 6) Check B+ Circuit For Open In Harness
   
   Ensure SSR is disconnected. Using a DVOM, measure resistance of B+ circuit between SSR harness connector and secondary AIR system dedicated fuse output terminal. See Fig 2. If resistance is less than 5 ohms, check VPWR circuit for short to GND. Replace dedicated fuse, reconnect SSR and go to step  8). If resistance is 5 ohms or more, repair open in B+ circuit. Reconnect SSR and replace dedicated fuse.
7. 7) DTC P0411: Visually Inspect EAIR Pump Hoses & Air Silencer
   
   Check EAIR pump air hoses from pump to AIR diverter valves for cracks, obstructions, water or ice (in colder climates). Check for damaged exhaust system. Check AIR silencer for obstructions. Repair as necessary. If components and hoses are okay, go to next step.
CAUTION: Overheating and damage may occur to EAIR pump if operated in OUTPUT TEST MODE for longer than 2 minutes.
8. 8) Check EAIR Pump Operation
   Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, enter OUTPUT TEST MODE. If EAIR pump operates, turn ignition switch to OFF position and go to step  17). If EAIR pump does not operate, fault may be intermittent. Go to TEST Z, step  1). If no intermittent faults are found, go to step  13).
9. 9) Check For Vacuum At AIR Diverter Valves
   
   Ensure ignition switch is turned to OFF position. Connect scan tool to Data Link Connector (DLC). Connect a vacuum gauge to AIR diverter valve(s) control vacuum hose. Using a hand vacuum pump, apply 16 in. Hg of vacuum to vacuum supply hose (intake manifold side) of AIR by-pass solenoid. Turn ignition switch to ON position. Using scan tool, enter OUTPUT TEST MODE. Vacuum should be present on vacuum gauge. If vacuum is present, go to next step. If vacuum is not present, go to step  32).
NOTE: On 2-valve systems, ensure air flows from both valves.
10. 10) Check AIR Diverter Valve Integrity
    Turn ignition switch to OFF position. Disconnect air tube from diverter valve(s) outlet side. Check diverter valve outlet(s) for heat damage and repair if necessary. Using hand vacuum pump, apply 16 in. Hg of vacuum to AIR diverter valve(s). Turn ignition switch to ON position. Using scan tool, enter OUTPUT TEST MODE. If air is present from AIR diverter valve(s), turn ignition switch to OFF position and check exhaust tube(s) from AIR diverter valve to exhaust manifold(s). If exhaust tube(s) from diverter valve are okay, go to next step. If air is not present from AIR diverter valve(s), turn ignition switch to OFF position and check hose from EAIR pump to AIR diverter valve(s). Replace as necessary. If hose is okay, replace appropriate AIR diverter valve(s).
NOTE: An intake manifold gasket leak can cause vacuum gauge reading to remain below normal range.
11. 11) Check Manifold Vacuum With Exhaust Manifold Disconnected
    Disconnect exhaust pipe from exhaust manifold. Start engine and gradually raise engine speed to 2000 RPM. Observe vacuum gauge reading response while maintaining increased engine RPM. If manifold vacuum is okay, exhaust restriction is downstream of exhaust manifold. Reconnect exhaust system to exhaust manifold and go to next step. If manifold vacuum is low or slow to respond, restriction is present in exhaust manifold. Check exhaust manifold for restrictions. If restrictions are present and are unable to be removed, replace exhaust manifold.
12. 12) Check Manifold Vacuum With Muffler & Tailpipe Asembly Disconnected
    
    Disconnect muffler and tailpipe assembly from rear of catalytic converter. Start engine and gradually raise engine speed to 2000 RPM. Observe vacuum gauge reading response while maintaining increased engine RPM. If manifold vacuum is now okay, fault is in muffler and tailpipe assembly. Repair as necessary. If manifold vacuum is still not okay, fault is in catalytic converter. Replace catalytic converter. After replacing catalytic converter, check muffler and tailpipe assembly for debris from faulty catalytic converter.
13. 13) Check Voltage On EAIR Monitor (EAIRM) Circuit
    
    Connect scan tool to Data Link Connector (DLC). Turn ignition switch to OFF position. Disconnect EAIR pump. Turn ignition switch to ON position. Using scan tool, enter OUTPUT TEST MODE. Using a DVOM, measure voltage of EAIRM circuit between EAIR pump harness connector and negative battery terminal. See Fig 2. If voltage is more than 10.5 volts for 20-30 seconds after a 5-10 second delay, go to step  15). If voltage is not as specified, go to next step.
14. 14) Check EAIR GND Circuit For Open
    
    Using a DVOM, measure resistance between EAIR pump harness connector GND terminal and negative battery terminal. See Fig 2. If resistance is less than 5 ohms, go to step  21). If resistance is 5 ohms or more, repair open in GND circuit.
15. 15) Check Air Hose To EAIR Pump
    
    Disconnect EAIR pump air inlet hose. Check hose for cracks, binding, obstructions, water or ice (in colder climates). If hose is okay, go to step  17). If hose is not okay, replace hose and go to step  17).
16. 16) Check Solid State Relay Output
    
    Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Reconnect AIR by-pass solenoid. Reconnect PCM harness connector. Ensure SSR is connected. Turn ignition switch to ON position. Using scan tool, select AIR and AIRM PIDs from PID/DATA MONITOR & RECORD menu. Compare AIR and AIRM PID readings. If both PID readings indicate ON, replace SSR. If either PID value indicates OFF, fault may be intermittent. Go to TEST Z, step  1). If no intermittent faults are found, replace PCM.
NOTE: Water contamination in EAIR pump will shorten life of pump.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 17) to step 19). No test procedures have been omitted.
17. 17) Check Air Pump For Water
    Turn ignition switch to OFF position. Disconnect EAIR pump air hoses and harness connector. Check EAIR pump for water. If water is present, replace EAIR 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).
18. 19) DTC P1413: Check B+ Circuit Voltage To Solid State Relay
    
    This DTC indicates EAIRM circuit is low indicating EAIR pump is off when PCM is commanding EAIR pump on. Possible causes are:
    • EAIRM Circuit Open Or Short To VPWR
    • B+ Circuit Open
    • Faulty PCM
    • Faulty EAIR Pump
    • Faulty Solid State Relay (SSR)

    Turn ignition switch to OFF position. Disconnect SSR harness connector. Turn ignition switch to ON position. Using a DVOM, measure voltage of B+ circuit between chassis ground and SSR harness connector. See Fig 2. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, go to step  26).

19. 20) Check For VPWR To SSR
    
    Turn ignition switch to ON position. Using a DVOM, measure voltage of VPWR circuit between chassis ground and SSR harness connector. See Fig 2. 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 between PCM and SSR.
20. 21) Check Voltage On EAIR Monitor (EAIRM) Circuit
    
    Turn ignition switch to OFF position. Ensure scan tool is connected to Data Link Connector (DLC). Reconnect SSR harness connector. Disconnect EAIR pump harness connector. Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE  under ADDITIONAL SYSTEM FUNCTIONS. Select START to turn outputs ON. Using scan tool, select AIRM PID from PID/DATA MONITOR & RECORD menu. If AIRM PID value indicates ON, remain in OUTPUT TEST MODE and go to step  25). If AIRM PID value indicates OFF and DTC P0411 is present, replace EAIR pump, remain in OUTPUT TEST MODE and go to next step.
21. 22) Check EAIRM Circuit Voltage To PCM
    
    Ensure ignition switch is turned to ON position. Using scan tool, select AIRM PID from PID/DATA MONITOR & RECORD menu. If AIRM PID value indicates ON, replace PCM. If AIRM PID value indicates OFF, go to next step.
22. 23) Check EAIRM Circuit For Open In Harness
    
    Turn ignition switch to OFF position. Disconnect SSR and EAIR pump harness connectors. Using a DVOM, measure resistance of EAIRM circuit between PCM harness connector and SSR harness connector. See Fig 2. Using a DVOM, measure resistance of EAIRM circuit between SSR harness connector and EAIR pump harness connector. If either resistance measurement is 5 ohms or more, repair open in EAIRM circuit. If both resistance measurements are less than 5 ohms, go to next step.
23. 24) Check EAIRM Circuit For Short To Ground
    
    Using a DVOM, measure resistance between PCM harness connector EAIRM and PWR GND circuit terminals. See Fig 2. If resistance measurement is more than 10 k/ohms, replace SSR. If resistance measurement is 10 k/ohms or less, repair short to ground in EAIRM circuit.
24. 25) Check EAIRM Circuit Voltage To PCM
    
    Reconnect EAIR pump. Reconnect PCM harness connector. Turn ignition switch to ON position. Ensure scan tool is still in OUTPUT TEST MODE and all outputs are selected ON. Using scan tool, select AIRM PID from PID/DATA MONITOR & RECORD menu. If AIRM PID value indicates ON, replace PCM. If AIRM PID value indicates OFF, repair open in EAIRM circuit.
25. 26) Check B+ Circuit For Open In Harness
    
    Using a DVOM, measure resistance of B+ circuit between SSR harness connector and SSR dedicated fuse. See Fig 2. If resistance is less than 5 ohms, replace SSR dedicated fuse. If resistance is 5 ohms or more, repair open in B+ circuit.
26. 27) DTC P1414: Check EAIR Monitor (EAIRM) Circuit Continuity
    
    This DTC indicates EAIRM circuit is low indicating EAIR pump is off when PCM is commanding EAIR pump on. Possible causes are:
    • EAIRM Circuit Open
    • EAIR Circuit Shorted To PWR
    • Faulty Solid State Relay (SSR)
    • Open EAIR Pump GND
    • Faulty EAIR Pump
    • Faulty PCM

    Turn ignition switch to OFF position. Disconnect EAIR pump and SSR harness connectors. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of EAIRM circuit between PCM harness connector and EAIR pump harness connector. See Fig 2. If resistance is 5 ohms or more, repair open in EAIRM circuit. If resistance is less than 5 ohms, go to next step.

27. 28) Check EAIR Pump For Open
    
    Using a DVOM, measure resistance between both EAIR pump terminals. If resistance is .5-5.0 ohms, go to next step. If resistance is not .5-5.0 ohms, replace EAIR pump.
28. 29) Check EAIRM Circuit For Short To PWR In Harness
    
    Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and PCM harness connector EAIRM circuit terminal. See Fig 2. If voltage is 10.5 volts or less, go to next step. If voltage is more than 10.5 volts, repair short to PWR in EAIRM circuit.
29. 30) Check Solid State Relay Output
    
    Reconnect all connectors. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE  under ADDITIONAL SYSTEM FUNCTIONS. Select START to turn outputs ON. Access AIR and AIRM PIDs from PID/DATA MONITOR & RECORD menu. Observe PID values. If both PID readings indicate ON, replace SSR. If either PID value indicates OFF, replace PCM.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 30) to step 32). No test procedures have been omitted.
30. 32) Check Vacuum Hose Integrity
    
    Turn ignition switch to OFF position. Remove vacuum hose between intake manifold and AIR diverter valve(s). Check hose for cracks, binding, obstructions, water or ice (in colder climates). Replace or repair hose as necessary. If hose is okay, go to next step.
31. 33) Check AIR By-Pass Solenoid Electrical Operation
    
    Ensure scan tool is connected to DLC. Disconnect air by-pass solenoid connector. Turn ignition switch to ON position. Using scan tool, select OUTPUT TEST MODE. Connect DVOM between both AIR by-pass solenoid harness connector terminals. See Fig 2. Observe DVOM voltage reading while cycling outputs ON and OFF. If voltage reading cycles more than .5 volt, remain in OUTPUT TEST MODE and go to next step. If voltage reading does not cycle more than .5 volt, turn ignition switch to OFF position and go to step  35).
32. 34) Check AIR By-Pass Solenoid Mechanical Operation
    
    Ensure scan tool is in OUTPUT TEST MODE. Reconnect AIR by-pass solenoid harness connector. Disconnect source vacuum hose from AIR by-pass solenoid. Connect hand vacuum pump to vacuum hose. Apply 16 in. Hg to AIR by-pass solenoid. Observe DVOM while cycling outputs ON and OFF. If vacuum does not release as outputs cycle ON and OFF, replace AIR by-pass solenoid. If vacuum releases as outputs cycle ON and OFF, repair vacuum hose between AIR by-pass solenoid and intake manifold vacuum tree. If hose is okay, go to TEST Z, step  2).
33. 35) Check Air By-Pass Solenoid Resistance
    
    Turn ignition switch to OFF position. Disconnect AIR by-pass solenoid harness connector. Using a DVOM, measure resistance between both 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. 36) Check VPWR Circuit For Open In Harness
    
    Turn ignition switch to ON position. Using a DVOM, measure VPWR circuit voltage between negative battery terminal and AIR by-pass solenoid harness connector. 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. 37) Check EAIR Circuit For Open In Harness
    
    Turn ignition switch to OFF position. Disconnect SSR harness connector. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of EAIR circuit between PCM harness connector and SSR harness connector. See Fig 2. Using a DVOM, measure resistance of EAIR circuit between PCM harness connector and AIR by-pass solenoid harness connector. If either resistance measurement is 5 ohms or more, repair open in EAIR circuit. If both resistance measurements are less than 5 ohms, go to next step.
36. 38) Check EAIR Circuit For Short To Ground In Harness
    
    Turn ignition switch to OFF position. Using a DVOM, measure resistance between PCM harness connector EAIR and PWR GND circuit terminals. See PCM PWR GND, SIG RTN & VREF TERMINAL IDENTIFICATION  table. See Figure and Fig 2 . If both resistance measurements are more than 10 k/ohms, go to next step. If either resistance measurement is 10 k/ohms or less, repair short to GND in EAIR circuit.
37. 39) Check EAIR Circuit For Short To VPWR In Harness
    
    Using a DVOM, measure resistance between PCM harness connector EAIR and PWR GND circuit terminals. See PCM PWR GND, SIG RTN & VREF TERMINAL IDENTIFICATION  table. See Figure and Fig 2 . If resistance is more than 10 k/ohms, replace PCM. If resistance is 10 k/ohms or less, repair short to PWR in EAIR circuit.