Diagnostic Aids

NOTE: After each service or repair procedure has been completed, reconnect all components. Go to step 38) and perform IMRC REPAIR VERIFICATION DRIVE CYCLE to ensure all EEC-V system is working properly and DTCs are no longer present.

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

Intake Manifold Runner Control (IMRC) Assembly
Accelerator Linkage
Air Cleaner Assembly
Air Inlet Tube
Clean Air Tube & Resonator
Throttle Body Assembly
IMRC Actuator Assembly
Wiring Harness Circuits (IMRC, IMRC MONITOR, SIG RTN, PWR GND & VPWR)
Powertrain Control Module (PCM)

NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION table of fault code setting condition.

FAULT CODE SETTING CONDITION

Fault Code	KOEO	KOER	Continuous Memory
P1512			HU15
P1513			HU15
P1516	HU15		HU15
P1517	HU15		HU15
P1518	HU15	HU15	HU15 HU15
P1519	HU15	HU15	HU15
P1520	HU15	HU15	HU15
P1537	HU15	HU15	HU15
P1539	HU15	HU15	HU15
P1549	HU65		HU65

NOTE: If directed here for a part throttle engine running problem, go to step 4).

1) Check For Incorrect Idle Speed

Ensure engine is at normal operating temperature. Start engine and allow to idle. Check idle speed. If idle speed is correct, go to next step. If idle speed is high, check if throttle arm fully returns and contacts return stop. Repair as necessary and go to step 6). If idle speed is low, go to step 7).

2) Check Accelerator Linkage

If linkage sticks, binds or grabs, go to next step. If linkage operation is okay, go to step 4).

3) Inspect Accelerator/Speed Control Cables

Turn ignition switch to OFF position. Disconnect accelerator and speed control cables from throttle body. Inspect cables for freedom of travel from accelerator pedal/speed control device to throttle body linkage cable connector. If cables move freely, go to next step. If cables do not move freely, repair as necessary.

4) Check Functionality Of Throttle Position Sensor

Turn ignition switch to ON position. Using scan tool, select TP V PID from PID/DATA MONITOR & RECORD menu. While observing PID reading, slowly open throttle to full wide open position. If PID voltage reading indicates a smooth reading during throttle movement, go to next step. If PID voltage reading does not indicate a smooth reading, replace TP sensor.

5) Check Air Filter & Inlet For Restrictions

Check air filter and inlet tube for restrictions. Check for plugging or blockage through air inlet to throttle body. Clean inlet and filter or replace filter as necessary. If air filter and inlet tube are okay, go to next step.

6) Check Positive Crankcase Ventilation System

A high idle may indicate incorrect PCV valve size or a vacuum leak. Check PCV valve connections for leaks or cracks. Remove PCV valve and check for plugged or incorrect valve. Repair as necessary. If PCV valve is okay reinstall PCV valve and go to step 9) (high idle concerns) or go to next step (all others).

7) Check IAC Solenoid Function

Ensure all accessories are off. With engine operating at idle, disconnect IAC solenoid connector. If engine speed decreases or engine stalls, go to next step. If engine speed does not change, go to step 9) (high idle concern) or replace IAC solenoid (low idle concern).

NOTE: Not all applications have a throttle plate hole. If not equipped, go to SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V (GASOLINE) article.

8) Check Throttle Body Plate Hole For Plugging
Remove resonator from throttle body assembly. Inspect throttle plate hole for restriction. Repair as necessary. If throttle plate hole is not restricted, go to SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V (GASOLINE) article and diagnose by symptom.

9) Check For Vacuum Leaks

Start engine and allow to idle. Inspect inlet air system from MAF sensor to intake manifold for cracks, loose connections or faulty gaskets. Inspect intake manifold, EGR diaphragm and vacuum hoses for leaks. Repair as necessary. If no faults are found, disconnect IAC valve connector. If idle speed does not drop, replace IAC valve. If idle speed drops, go to next step.

10) Check Throttle Body

Turn ignition switch to OFF position. Remove throttle body. With throttle fully closed, ensure light cannot be seen between throttle bore and plate. Snap throttle from wide open to closed position several times. Slowly cycle throttle from closed to wide open position. Check for freedom of travel especially during initial throttle opening. If faults are present, replace throttle body. If throttle body is okay, fault cannot be duplicated or identified at this time. Reinstall throttle body and check for additional symptoms and repair as necessary. See TROUBLE SHOOTING - NO CODES - EEC-V (GASOLINE) article.
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) DTC P1512, P1513, P1516-P1520, P1537 Or P1538

DTCs P1512, P1513 and P1519 indicate IMRC may be stuck closed. KOEO or Continuous Memory self-test failed when IMRC monitor circuit signal exceeded expected calibrated range with IMRC activated. Possible causes are.
- Faulty Vacuum Hoses
- Faulty Vacuum Solenoid
- Faulty Vacuum Actuator
- IMRC Actuator Cable, Lever Or Gears Binding Or Seized
- Cables Improperly Routed, Binding Or Seized
- Faulty IMRC Actuator
- Damaged Or Disconnected IMRC Housing Return Springs
- Lever Return Stop Obstructed Or Bent
- Lever Wide Open Stop Obstructed Or Bent
- IMRC Monitor Circuit Open Or Shorted To VREF
- IMRC SIG RTN Circuit Open Or Shorted To VPWR Or GND
- IMRC VPWR Circuit Open
DTCs P1516 (IMRC input error bank No. 1) and P1517 (IMRC input error bank No. 2) indicate KOEO or Continuous Memory self-test failed when IMRC monitor circuit signal falls below or exceeds expected calibrated range. Possible cause is binding, seizing, damage or obstruction of IMRC mechanical system.

DTCs P1518, P1537 and P1538 may indicate IMRC stuck open. KOEO or Continuous Memory self-test failed when IMRC monitor circuit signal falls below expected calibrated range at closed throttle. Possible causes are.
- IMRC SIG Circuit Shorted To PWR GND Or SIG RTN
- Faulty IMRC Actuator
- Faulty Powertrain Control Module (PCM)
WARNING: Be careful when operating IMRC by hand. IMRC return springs are strong and cause plates to close suddenly.

On models equipped with cable operated IMRC, check IMRC cables for correct routing and possible binding. Ensure cable core wire (if equipped) has slack at IMRC housing and that lever contacts close plate stop screw. Ensure return springs operate properly and plates open and close fully. On models with vacuum operated systems, engine must run for 20 seconds then perform KOEO ON-DEMAND SELF-TEST. On all models, operate IMRC plates at intake manifold while checking for binding and sticking. If any faults are found, go to next step. If no faults are found, go to step 17).

16) Perform IMRC Physical Test

On Escort and Focus, remove actuator assembly. On all other models, disconnect IMRC linkage or cable(s) from intake runner(s). Rotate IMRC lever to fully open and back to fully closed positions while checking for binding or sticking. Feel for return spring tension. Levers should fully open and close without obstruction. If any faults are found, clean or repair as necessary. If no faults are found, replace IMRC actuator.

17) Perform IMRC Functional Test

Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. On Focus, monitor IMRCM PID voltage. If IMRCM PID voltage reading is less than one volt, go to step 23). On all other models, if IMRC plates open immediately when ignition switch is turned to ON position, go to step 23). If IMRCM PID voltage reading is one volt or more on Focus, or if IMRC plates do not open immediately on all other models, use scan tool and access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Select START to turn all outputs ON. When IMRC is commanded ON, lever(s) should rotate to full open position. One or both levers should contact wide open stop (one lever being slightly off is acceptable). On Escort and Focus, listen for IMRC to actuate. On all models, IMRC levers should cycle from fully closed and remain in fully open position while outputs are ON. If IMRC levers do not operate as specified, go to next step. If IMRC levers operate as specified, go to step 25).

18) Check IMRC Actuator VPWR Circuit For An Open In Harness

Turn ignition switch to OFF position. Disconnect IMRC actuator harness connector. Turn ignition switch to ON position. Using a DVOM, measure voltage of VPWR circuit between negative battery terminal and IMRC actuator harness connector. See Fig 1-Fig 3 . If voltage is more than 10.5 volts, go to step 20) for Escort and Focus, or go to next step for all other models. If voltage is 10.5 volts or less, repair open in VPWR circuit.
NOTE: IMRC actuator harness connector may also be referred to as IMRC harness connector.

Fig 1: Identifying IMRC Actuator Wiring Harness Connector Terminals (Escort & Focus 2.0L 2V)
Courtesy of FORD MOTOR CO.

Fig 2: Identifying IMRC Wiring Harness Connector Terminals (Econoline & Pickup 4.2L, & Windstar 3.8L)
Courtesy of FORD MOTOR CO.

Fig 3: Identifying IMRC Wiring Harness Connector Terminals (Contour, Cougar & Mystique 2.5L)
Courtesy of FORD MOTOR CO.

19) Check IMRC GND Circuits For Open In Harness

Measure voltage between VPWR terminal and SIG RTN terminal at IMRC actuator 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 SIG RTN circuit.

20) Verify Driver Circuit

Turn ignition switch to OFF position. Connect a test light between VPWR terminal and IMRC SIGNAL terminal at IMRC actuator harness connector. Test light should be off. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Turn all outputs ON. If test light is now on, go to step 32). If test light is still off, go to next step.

21) Check For Open IMRC Driver Circuit

Disconnect PCM connector(s). Measure resistance of IMRC SIGNAL circuit between PCM connector terminal and IMRC actuator harness connector. See Figure or Figure and Fig 1-Fig 3 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in IMRC SIGNAL circuit.

22) Check IMRC Driver SIGNAL Circuit For Short To VPWR In Harness

Turn ignition switch to ON position. Measure voltage between IMRC SIGNAL terminal at actuator harness connector and ground. If voltage is less than 10.5 volts, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . If voltage is 10.5 volts or more, repair short to power.

23) Check IMRC Driver SIGNAL Circuit For Short To GND Or Monitor Circuit (PCM Connected)

Ensure PCM is connected. Measure resistance between IMRC SIGNAL terminal and SIG RTN and PWR GND terminals at IMRC actuator harness connector. Measure resistance between IMRCM terminal and SIG RTN and PWR GND terminals at IMRC actuator harness connector. If all resistance readings are more than 10 k/ohms, replace IMRC actuator. If any resistance reading is 10 k/ohms or less, go to next step.

24) Check IMRC Driver SIGNAL Circuit For Short To GND Or Monitor Circuit (PCM Disconnected)

Disconnect PCM connector(s). Measure resistance between IMRC SIGNAL terminal and SIG RTN and PWR GND terminals at IMRC actuator harness connector. Measure resistance between IMRCM terminal and SIG RTN and PWR GND terminals at IMRC actuator harness connector. If all resistance readings are more than 10 k/ohms, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . If any resistance reading is 10 k/ohms or less, repair short in appropriate circuit.

25) Check IMRCM PID To Determine Path For Possible Short

Using scan tool, select IMRCM PID from PID/DATA MONITOR & RECORD menu. On models with 3.8L or 4.2L, PID value should be about 2.5 volts. On all other models, PID value should be about 4.5 volts. On all models, if PID voltage is as specified, go to next step. If PID voltage is not as specified, go to step 30).

26) Check IMRCM PID To Determine A Short To VPWR

Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Access IMRCM PID. Turn all outputs ON. If PID value is less than one volt, go to next step. If PID value is one volt or less, go to step 32).

27) Check For Short To Power In IMRC Monitor Circuit

Disconnect IMRC actuator connector. Turn ignition switch to ON position. Measure voltage between IMRCM terminal at IMRC actuator 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, go to step 29).

28) Check For Short With PCM Disconnected

Turn ignition switch to OFF position. Disconnect PCM connector(s). Turn ignition switch to ON position. Measure voltage between IMRCM terminal at IMRC actuator harness connector and negative battery terminal. If voltage is more than 10.5 volts, repair short in IMRCM circuit. If voltage is 10.5 volts or less, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE .

29) Check For IMRC Actuator Short

Turn ignition switch to OFF position. Measure resistance between VPWR terminal and IMRCM terminal at IMRC actuator harness connector. If resistance is 10 k/ohms or less, replace IMRC actuator. If resistance is more than 10 k/ohms, no fault is indicated at this time. Go to TEST Z and check for intermittents. If no intermittent faults are found, replace PCM.

30) Check For Short To Ground

Ensure ignition switch is in ON position. Using scan tool, select IMRCM PID from PID/DATA MONITOR & RECORD menu. Note PID voltage reading. Disconnect IMRC actuator connector. If PID voltage changed from less than one volt to about 4.5 volts, replace IMRC actuator. If voltage does not change from less than one volt to about 4.5 volts, go to next step.

31) Check For Short To Ground

Turn ignition switch to OFF position. Disconnect PCM connector(s). Measure resistance between IMRCM terminal at IMRC actuator harness connector and ground. If resistance is more than 10 k/ohms, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . If resistance is 10 k/ohms or less, repair short in IMRCM circuit.

32) Check IMRC Monitor Circuit Response

Turn ignition switch to OFF position. Disconnect IMRC actuator connector. Turn ignition switch to ON position. Using scan tool, select IMRCM PID from PID/DATA MONITOR & RECORD menu. Note PID voltage reading while connecting a jumper wire between IMRCM terminal at IMRC actuator harness connector and ground. If PID voltage changed from about 4.5 volts to less than one volt, go to next step. If PID voltage did not change from about 4.5 volts to less than one volt, go to step 36).

33) Check Circuit Continuity

Turn ignition switch to OFF position. Reconnect PCM connector(s). Measure resistance between negative battery terminal and SIG RTN or CHASSIS GROUND terminal at IMRC actuator harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, go to step 35).

34) Check IMRCM Circuit For Intermittent Open

Ensure ignition switch is turned to OFF position. Using a DVOM, measure resistance of IMRCM circuit between PCM harness connector and IMRC harness connector. Wiggle and bend wiring harness between IMRC harness connector and PCM harness connector. A fault will be indicated by a change in resistance measurement. If fault is indicated, isolate fault and repair as necessary. If no faults are indicated, replace IMRC actuator.

35) Check Circuit Continuity With PCM Disconnected

Disconnect PCM connector(s). Measure resistance of SIG RTN or CHASSIS GROUND terminal at IMRC actuator harness connector and PCM connector. If resistance is 5 ohms or more, repair open in SIG RTN or CHASSIS GROUND circuit. If resistance is less than 5 ohms, fault may be intermittent. Go to TEST Z . If no intermittent faults are found, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE .

36) Check IMRCM Or SCVM Circuit Continuity

Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance of IMRCM circuit between PCM harness connector and IMRC harness connector and PCM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in IMRCM circuit.

37) Check For Intermittent Fault

Ensure ignition switch is turned to OFF position. Using a DVOM, measure resistance of IMRCM circuit between PCM harness connector and IMRC actuator harness connector while wiggling wiring harness between IMRC actuator connector and PCM harness connector. See Figure or Figure and Fig 1-Fig 3 . A fault will be indicated by change in resistance measurement. If fault is indicated, isolate fault and repair as necessary. If no faults are indicated, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE .

38) IMRC Repair Verification Drive Cycle

Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Perform PCM RESET PROCEDURE under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. Using scan tool, access appropriate IMRC or IMSC, and IMRCM or SCVM PIDs. Test drive vehicle. Complete 3 accelerations from a complete stop to a speed requiring engine speed of more than 3500 RPM. Observe PID voltage reading changes. Stop vehicle. Perform QUICK TEST and retrieve all DTCs. If any DTCs are present, go to appropriate system test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are present, testing is complete.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 38) to step 65). No test procedures have been omitted.

65) DTC P1549: Perform Visual Inspection

This fault indicates IMTV circuit fault. Possible causes are:
- VPWR Circuit Open
- Open Or Shorted Signal Circuit
- Faulty IMT Valve
- Faulty Powertrain Control Module (PCM)
Turn ignition switch to OFF position. Check IMT valve system. Ensure harness connector is installed properly. Repair as necessary. If no faults are found, go to next step.

NOTE: Vehicle must be driven if rev limiter does not allow engine speed to exceed 3500 RPM while performing this step.

66) Check PCM Driver Command
Start engine. Using scan tool, select IMTV PID from PID/DATA MONITOR & RECORD menu. Observe PID value and increase engine speed to about 3500 RPM. PID value should indicate 100 percent then drop to 50 percent when engine RPM is more than 3500. If PID value is as specified, PCM driver command is okay. Go to next step. If PID value is not as specified, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE .

67) Check For Open IMT Valve Actuator Or Vacuum Solenoid VPWR Circuit

Turn ignition switch to OFF position. Disconnect IMT valve actuator connector. See Fig 4-Fig 5 . Turn ignition switch to ON position. Measure voltage between chassis ground and VPWR terminal at IMT valve actuator harness connector. If voltage is more than 10.5 volts, go to step 69). If voltage is 10.5 volts or less, repair open in VPWR circuit and retest system.

Fig 4: Identifying Intake Manifold Tuning Valve Vacuum Solenoid Wiring Harness Connector Terminals (Econoline 5.4L, Expedition & Pickup 4.6L, & Navigator 5.4L 4V)
Courtesy of FORD MOTOR CO.

Fig 5: Identifying Intake Manifold Tuning Valve Vacuum Solenoid Wiring Harness Connector Terminals (LS V6)
Courtesy of FORD MOTOR CO.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 67) to step 69). No test procedures have been omitted.

69) Check For Open Circuit

Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect for damaged terminals and repair if necessary. Using a DVOM, measure resistance of IMTV SIG circuit between PCM harness connector and IMTV actuator harness connector. See Fig 4 or Fig 5 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in IMTV SIG circuit.

70) Check IMTV Actuator Signal Circuit For Short To PWR GND

Using a DVOM, measure resistance between PCM harness connector IMTV SIG circuit terminal and PWR GND circuit terminals. See WIRING DIAGRAMS article. See Figure, Figure, Fig 4 or Fig 5 . If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short between IMTV SIG and PWR GND circuit(s).

71) Check IMTV SIG Circuit For Short To VPWR

Turn ignition switch to ON position. Using a DVOM, measure voltage between PCM harness connector IMTV SIG and VPWR circuit terminals. See WIRING DIAGRAMS. See Figure or Figure . If voltage is one volt or more, repair short between IMTV SIG and VPWR circuit(s). If voltage is less than one volt, go to next step.

72) Check PCM Driver

Turn ignition switch to OFF position. Reconnect PCM harness connector. Connect scan tool to Data Link Connector (DLC). Connect a test light between negative battery terminal and IMTV actuator harness connector VPWR terminal. See Fig 4 or Fig 5 . Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Command all outputs ON. If test light was off with all outputs OFF and illuminates with all outputs ON, go to next step. If test light does not operate as specified, replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Program PCM. See FLASH VEHICLE IDENTIFICATION BLOCK PROCEDURE . Verify symptom is no longer present.

73) Check IMT Valve Shutter

Remove IMT valve. Check IMT valve shutter for damage. Rotate shutter and check for binding. Replace IMT valve as necessary. If IMT valve is okay, leave IMT valve disassembled and go to next step.

74) Check IMT Valve Actuator

Reconnect IMT valve actuator connector. Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Observe IMT valve shutter and turn all outputs ON. If shutter rotates, no fault is indicated at this time. Go to TEST Z . If shutter does not rotate, replace IMT valve actuator. Verify symptom is no longer present.