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Code 538 Displayed: System Failed To Recognize WOT Test Ford Mustang IV

Engine Controls - Tests W/codes - Eec-Iv (5.0L): Diagnosis 12 illustrations ~13608 words

Code 538 Displayed: System Failed To Recognize WOT Test

Repeat KOER SELF-TEST as follows

  1. Activate SELF-TEST.
  2. Start engine.
  3. Observe ID Code start of test.
  4. Observe Dynamic Response Code 1 (Code 0 with STAR tester).
  5. Perform brief WOT.
  6. Testing is complete; Diagnostic Test Code (DTC) output begins.

Ensure vehicle speed reached 2000 RPM during WOT. If engine speed did not reach 2000 RPM, check for binding throttle linkage. If Code 538 is present, replace PCM. Repeat QUICK TEST . If Code 538 is not present, vehicle has passed dynamic response test. Service other codes if necessary.

The MIL is turned on when PCM detects a fault in EEC circuit(s). The light will remain on as long as fault remains in system.

Perform this test only when instructed by QUICK TEST or if directed by CIRCUIT TEST QA . This test does not include procedure for models with electronic instrument panel. To prevent replacing good components, be aware that fuse, bulb or bulb socket may be cause of problem. This test is only intended to diagnose

Scheme 106

Scheme 106: Diagnostic Aids
Scheme 106: Diagnostic Aids
  1. STO/MIL circuit.
  2. Faulty PCM. (Scheme 106): Identifying Data Link Connector (DLC) Terminals TEST PIN WIRE COLOR IDENTIFICATION Application Test Pin No. Wire Color STO/MIL 17 Pink/Light Green DATA + 18 Tan/Orange DATA - 19 Pink/Light Blue
  1. 1) Malfunction Indicator Light (MIL) Always On If vehicle will not start, go to appropriate circuit test: For Distributor Ignition (DI) systems, «CIRCUIT TEST AA»(ref-23127-S11072071312001010300000) . For distributorless ignition systems (low data rate), CIRCUIT TEST AB. For distributorless ignition systems (high data rate), CIRCUIT TEST AC. If vehicle will start, service all KOEO and Continuous Memory Codes before proceeding with this test. Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pins No. 17 and 40 at breakout box. If resistance is 5 ohms or more, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If resistance is less than 5 ohms, repair short between test pin No. 17 and Data Link Connector (DLC) or MIL. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  2. 2) Malfunction Indicator Light (MIL) Does Not Light If vehicle will not start, go to step 1). Turn ignition on. Measure voltage between negative battery terminal and ground side of MIL fuse. If voltage is more than 10.5 volts, go to step 4). If voltage is 10.5 volts or less, go to next step.
  3. 3) Check For Voltage At Fuse Turn ignition on. Measure voltage from negative battery terminal to power side of MIL fuse. If voltage is more than 10.5 volts, replace fuse. Verify repair by turning ignition on. If voltage is 10.5 volts or less, repair open MIL/B+ circuit. Verify repair by turning ignition on.
  4. 4) Check Voltage At B+ Circuit Turn ignition on. Measure voltage between B+ side of MIL bulb socket and negative battery terminal. If voltage is 10.5 volts or less, repair open in MIL circuit between fuse and bulb. Verify repair by turning ignition on. If voltage is more than 10.5 volts, go to next step.
  5. 5) Check MIL Bulb Response To Grounding Turn ignition off. Attach jumper wire between ground side of MIL bulb socket and chassis ground. Turn ignition on. If MIL light comes on, remove jumper wire, and go to next step. If MIL light does not come on, remove jumper wire. Replace MIL bulb socket. Turn ignition on to verify correct MIL operation.
  6. 6) Check Continuity Of MIL Circuit Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pin No. 17 at breakout box and MIL wiring harness connector terminal. If resistance is less than 5 ohms, replace PCM. Turn ignition on to verify correct MIL operation. If resistance is 5 ohms or more, repair open in ground side of MIL circuit. Turn ignition on to verify correct MIL operation. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 6) to step 10). No test procedures have been omitted.
  7. 10) MIL On Intermittently, Check For Intermittent Short From STO To Ground If vehicle does not start, go to step 1). MIL comes on when a fault code is present. Service all fault codes before proceeding. If no codes are output, proceed with this test. Enter KOEO wiggle test. See «CONTINUOUS MONITOR MODE (WIGGLE TEST)»(ref-23127-S28284472892001010300000) under QUICK TEST. Check DVOM for indication of fault while performing wiggle test on harness in the following areas: From Data Link Connector (DLC) to dash panel. Dash panel to PCM. Dash panel to Malfunction Indicator Light (MIL). If a fault is indicated, repair short to ground and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If a fault is not indicated, fault cannot be duplicated at this time. Testing is complete. 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.
  8. 15) MIL Flashes With Erratic Idle Symptoms indicate STI is grounded and PCM is performing self-test without tester installed. Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between STI connector and engine ground. If resistance is less than 10,000 ohms, repair short circuit. Reconnect PCM, and turn ignition on to verify correct MIL operation. If resistance is 10,000 ohms or more, MIL circuit is okay. Verify symptom, and test for other rough idle symptoms. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 15) to step 20). No test procedures have been omitted.
  9. 20) CHECK ENGINE Message Displayed If vehicle will not start, go to step 1). Perform «KOEO SELF-TEST»(ref-23127-S30488885572001010300000) . If result is Code 111-10-111 (pass code), fault is in instrument cluster. If pass code is not displayed, service codes as necessary. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 20) to step 25). No test procedures have been omitted.
  10. 25) Continuous Memory Code 529 Or 533: CHECK ENGINE Or CHECK DCL Message Displayed Codes 529 and 533 indicate circuit fault has occurred on Data Communications Link (DCL). These codes can occur alone or with another code. Fault will occur under following conditions: Code 529 indicates PCM or DCL circuit failure. Code 533 indicates DCL to electronic instrument cluster circuit failure. If vehicle does not start, go to step 1). If vehicle starts, clear continuous memory codes. Wait 5 minutes, and repeat «KOEO SELF-TEST»(ref-23127-S30488885572001010300000) . If result is pass code (Code 111-10-111), fault is in instrument cluster. If pass code is not displayed, service codes as necessary.

The IDM is an input signal to the PCM that verifies spark plug fire based on ignition coil primary discharge. IDM signal consists of a single pulse for each engine RPM. No IDM pulse indicates secondary ignition misfire.

Perform this test when directed by QUICK TEST. This test is only intended to diagnose EEC-IV portion of ignition system. For additional information on ignition system and component testing, see the I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L) article. To prevent replacing good components, be aware the following non-EEC related areas may be cause of problem

  1. Ignition Control Module (ICM).
  2. Ignition coil.
  3. Spark plugs and/or wires.
  4. Distributor.
  5. Secondary ignition short to ground.

This test is intended to diagnose

Scheme 107

Scheme 107
Scheme 107
  1. IDM circuit.
  2. Faulty PCM. (Scheme 107): IDM Circuit Schematic TEST PIN NO. 4 (IDM) WIRE COLOR IDENTIFICATION Application Wire Color Mustang White/Pink
  1. 1) Continuous Memory Code 211 Code 211 indicates 2 successive erratic Profile Ignition Pick-Up (PIP) pulses occurred, resulting in a possible engine miss or stall. Check for the following possible causes of fault: Loose wires or connectors. Arcing secondary ignition components. On-board transmitter equipment (2-way radio). If any of the above possible causes are present, repair as necessary. Clear code, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If problem is not found, go to next step. If vehicle does not start, go to IGNITION SYSTEMS in the «I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L)»(ref-23126) article.
  2. 2) Continuous Memory Code 212: Check IDM Circuit Continuity Continuous Memory Code 212 indicates loss of IDM input to PCM. Possible causes for this fault are: Open or shorted circuit in wiring harness. Faulty ICM. Faulty PCM. If vehicle is a no-start, see IGNITION SYSTEMS in the «I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L)»(ref-23126) article. If vehicle starts, go to next step.
  3. 3) Check IDM Circuit Continuity Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect ICM. Measure resistance between test pin No. 4 at breakout box and IDM circuit terminal at ICM wiring harness connector. If resistance is less than 5 ohms, go to step 5). If resistance is 5 ohms or more, repair open circuit, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 5). No test procedures have been omitted.
  4. 5) Check IDM Circuit For Short To Power (Except VREF) Turn ignition off. Leave ICM and PCM disconnected. Measure voltage between breakout box test pin No. 4 and negative battery terminal. Turn ignition on. Measure voltage between test pin No. 4 and test pins No. 40 and 60 at breakout box. If any reading is more than 10.5 volts, repair short circuit. Clear codes, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If both readings are 10.5 volts or less, go to next step.
  5. 6) Check IDM Circuit For Short To PIP & VREF Turn ignition off. Leave PCM and ICM disconnected. Remove scan tool (if applicable). For shorts to PIP, measure resistance between test pins No. 4 and No. 56 at breakout box. For shorts to VREF, measure resistance between test pins No. 4 and No. 26 at breakout box. If either resistance is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If each resistance is more than 10,000 ohms, go to next step.
  6. 7) Check IDM Circuit For Short To Ground Turn ignition off. Leave ICM and PCM disconnected. Measure resistance between test pin No. 4 and test pins No. 20, 40, 46 and 60 at breakout box. If each resistance is more than 10,000 ohms, go to next step. If any resistance is 10,000 ohms or less, repair short to ground in IDM circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  7. 8) Check ICM Turn ignition off. Connect PCM to breakout box. Reconnect ICM to wiring harness connector. Connect DVOM between test pins No. 4 and 16 at breakout box. Start engine. Observe DVOM for voltage surge while lightly tapping on ICM and Camshaft Position (CMP) sensor (if equipped) to simulate road shock. Wiggle all ICM and CMP sensor wiring and harness connectors. If fault (voltage surge) is not indicated, go to next step. If fault (voltage surge) is indicated, disconnect and inspect wiring harness connectors and terminals for damage. Repair as necessary. If connectors and terminals are okay, check ignition system. See the «I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L)»(ref-23126) article.
  8. 9) Check PCM & Harness Connectors Ensure engine is still running and DVOM is still connected between test pins No. 4 and 16 at breakout box. While observing DVOM, wiggle and bend wiring harness, a small section at a time, from ICM and CMP sensor (if equipped) to cowl. Also, check harness from cowl to PCM. If fault is indicated, isolate fault and repair as necessary. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If no fault is found, go to next step.
  9. 10) Check PCM & Harness Connectors Turn ignition off. Disconnect PCM 60-pin connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. If connector is damaged, repair as necessary. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If connector is okay, go to next step.
  10. 11) Check PCM For Short To Power Turn ignition off. Connect PCM to breakout box. Disconnect the following sensors as applicable. On vehicles with remote mounted ICM and CMP, disconnect ICM and CMP wiring harness connector. On all other models, disconnect ICM wiring harness connector. On all models, measure voltage between test pin No. 4 at breakout box and chassis ground. Turn ignition on. Measure voltage between test pin No. 4 and test pins No. 40 and 60 at breakout box. If any reading is more than 10.5 volts, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If both readings are 10.5 volts or less, go to next step.
  11. 12) Check PCM For Short To Ground Turn ignition off. Leave PCM connected to breakout box. Disconnect ICM and CMP. Measure resistance between test pin No. 4 and test pins No. 40, 46 and 60 at breakout box. If all readings are more than 10,000 ohms, check ignition system. See the «I - SYSTEM/COMPONENT TESTS - EEC-IV (5.0L)»(ref-23126) article. If any reading is 10,000 ohms or less, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .

During this test, a short to SIG RTN (pin No. 46) may be indicated along with an actual short to PWR GND when 4-wire HO2S is connected to vehicle wiring harness.

Aftermarket devices, such as alarm system, may cause SELF-TEST to abort if wiring is connected to certain EEC components. If a device is installed, disconnect it completely from EEC system. Before continuing with this circuit test, restore EEC circuits to original state and repeat QUICK TEST .

Perform this test when directed by QUICK TEST or other test procedures. This test is intended to diagnose

Scheme 108

Scheme 108: Diagnostic Aids
Scheme 108: Diagnostic Aids
  1. Powertrain Control Module (PCM).
  2. EEC power relay.
  3. Constant Control Relay Module (CCRM).
  4. Wiring harness circuits (HO2S, SIG RTN, STO, STI, VPWR and VREF). (Scheme 108): No Codes/Codes Not Listed Circuits TEST PIN WIRE COLOR IDENTIFICATION Application Wire Color TEST PIN NO. 17 (STO/MIL) Pink/Light Green TEST PINS NO. 37 & 57 (VPWR) Red TEST PIN NO. 46 (SIG RTN) Gray/Red TEST PIN NO. 48 (STI) White/Purple
  1. Check VREF Voltage At Data Link Connector (DLC) Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Turn ignition on. Measure voltage between test pin No. 26 at breakout box and SIG RTN terminal at DLC. If reading is 4-6 volts, go to step 3). If reading is not 4-6 volts, go to next step.
  2. Check SIG RTN Circuit Continuity Turn ignition off. Disconnect PCM from breakout box. Measure resistance between test pin No. 46 at breakout box and SIG RTN terminal at DLC. If resistance is less than 5 ohms, go to «CIRCUIT TEST C»(ref-23127-S13417218072001010300000) . If resistance is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  3. Check STI Circuit Continuity Turn ignition off. Disconnect PCM from breakout box. Measure resistance between test pin No. 48 at breakout box and Self-Test Input (STI) terminal at pigtail connector. If resistance is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If resistance is less than 5 ohms, go to next step.
  4. Check STO Circuit Continuity Leave ignition off and PCM disconnected. Measure resistance between test pin No. 17 at breakout box and STO terminal at DLC. If resistance is less than 5 ohms, go to step 5). If resistance is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  5. Check HO2S Signal For Short To Power Leave PCM disconnected. Turn ignition on. Measure voltage between test pin No. 40 or 60 and HO2S SIGNAL test pin No. 29 or 44 at breakout box. For HO2S circuit schematics, see «CIRCUIT TEST H»(ref-23127-S07532022972001010300000) . If voltage is more than 2 volts, go to step 6). If voltage is 2 volts or less, go to step 7).
  6. Isolate Short To Harness Or HO2S Sensor Turn ignition off. Leave PCM disconnected. Disconnect right/rear HO2S sensor connector. Turn ignition on. Measure voltage between HO2S SIGNAL test pin No. 29 or 44 and test pin No. 40 or 60 at breakout box. If any reading is more than 2 volts, repair short to power in HO2S SIGNAL circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If voltage is 2 volts or less, replace right/rear HO2S sensor. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  7. Check STO Circuit For Short To Ground Turn ignition off. Leave PCM disconnected. Measure resistance between STO at DLC and engine ground. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in STO or MIL circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  8. Check If Power Relay Is Always On Leave ignition off and PCM disconnected. Connect DVOM between test pin No. 37 or 57 and test pin No. 40 or 60 at breakout box. Turn ignition on and then off. Wait 10 seconds. If voltage changes from more than 10.5 volts to less than 1.0 volt, go to step 10). If voltage does not change from more than 10.5 volts to less than 1.0 volt, go to next step.
  9. Check VPWR Circuit For Short To Power Turn ignition off. Leave PCM disconnected. Disconnect EEC power relay or Constant Control Relay Module (CCRM). Connect DVOM to test pin No. 37 or 57 and test pin No. 40 or 60 at breakout box. If voltage is more than 1.0 volt, repair VPWR circuit for a short to power. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If voltage is 1.0 volt or less, replace EEC power relay or CCRM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  10. Check Malfunction Indicator Light (MIL) Function If MIL is always on, go to «CIRCUIT TEST ML»(ref-23127-S36657672752001010300000) , step 1). If MIL is always off, go to «CIRCUIT TEST ML»(ref-23127-S36657672752001010300000) , step 2). If MIL is flashing, go to «CIRCUIT TEST ML»(ref-23127-S36657672752001010300000) , step 15). If MIL is working normally, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .

A right/rear HO2S shorted to power could prevent EEC system from entering self-diagnostics.

Perform this test when directed by QUICK TEST. This test is intended to diagnose

  1. Faulty Powertrain Control Module (PCM).
  2. KAPWR wiring harness circuits.

KAPWR Circuit Schematic. Scheme 109

Scheme 109: KAPWR Circuit Schematic
Scheme 109: KAPWR Circuit Schematic
ApplicationWire Color
MustangYellow

TEST PIN NO. 1 (KAPWR) WIRE COLOR IDENTIFICATION

Continuous Memory Code 512 may be displayed when power between PCM and KAPWR is interrupted. This code may be set when a breakout box is installed or battery is disconnected.

  1. Continuous Memory Code 512: Check KAPWR Circuit Voltage Code 512 indicates PCM power interruption in Keep-Alive Memory (KAM). Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure voltage between test pin No. 1 and test pin No. 40 or 60 at breakout box. Observe DVOM while wiggling small sections of EEC wiring harness from PCM to dash. If voltage is less than 10.5 volts, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If reading is 10.5 volts or more, go to next step.
  2. Inspect Wiring Harness Routing Ensure EEC wiring is not routed close to ignition components and secondary ignition wires. If necessary, reroute EEC wiring. Clear codes, and wait 5 minutes. Repeat «KOEO SELF-TEST»(ref-23127-S30488885572001010300000) . If Continuous Memory Code 512 is not repeated, service other codes as necessary. If no other codes are present, testing is complete. If Continuous Memory Code 512 is still present, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .

Perform this circuit test when directed by other CIRCUIT TESTS. This test is only intended to diagnose

  1. Throttle plate linkage.
  2. Test conditions.
  1. Check For Codes 121, 122 & 123 Disconnect cruise control servo wiring harness connector (if equipped). Perform «KOEO SELF-TEST»(ref-23127-S30488885572001010300000) . If Code 121, 122 or 123 is present, go to appropriate CIRCUIT TEST. See «DIAGNOSTIC TROUBLE CODE REFERENCE CHARTS»(ref-23127-S41550133352001010300000) , and service codes as necessary. If Code 111 (pass code) is displayed, go to next step. If no code is displayed, go to «CIRCUIT TEST QA»(ref-23127-S38026704502001010300000) .
  2. Check Throttle Linkage Check throttle and linkage for sticking and binding. If throttle and linkage are okay, replace Throttle Position (TP) sensor and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If throttle or linkage is binding, repair as necessary and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .

Perform this test only when directed by QUICK TEST. This test is intended to diagnose

  1. Battery voltage.
  2. Powertrain Control Module (PCM).
  1. Code 513 Code 513 indicated PCM internal voltage is not to specification. Possible causes for this fault are: Low battery voltage. Faulty PCM. Turn ignition off. Measure voltage between battery terminals. If voltage is more than 10.5 volts, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If voltage is 10.5 volts or less, service charging system as necessary. Repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .

Perform this test only when directed by CIRCUIT TEST AA , CIRCUIT TEST AB or CIRCUIT TEST AC. This test is intended to diagnose

  1. IAC system.
  2. EGR system.
  1. 1) IAC Check Try to start engine at part throttle. If engine starts and runs smoothly at part throttle, go to «CIRCUIT TEST KE»(ref-23127-S02077019202001010300000) , step 4). If engine does not run as described, go to step 3). If engine starts and idles smoothly, go to next step.
  2. 2) Check For RPM Drop Turn ignition off. Connect a tachometer to engine. Start engine. Disconnect IAC solenoid. If RPM drops or engine stalls, reconnect IAC solenoid and go to step 8). If RPM does not drop, «CIRCUIT TEST KE»(ref-23127-S02077019202001010300000) , step 4). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 2) to step 8). No test procedures have been omitted.
  3. 8) Check EGR Vacuum If vehicle is not equipped with EGR system, go to «CIRCUIT TEST H»(ref-23127-S07532022972001010300000) , step 2). If vehicle is equipped with EGR, disconnect and plug vacuum line at EGR valve. Attempt to start engine. If vehicle could not start previously and still does not start or if vehicle driveability fault is still present, go to next step. If vehicle did not start previously but starts now or if driveability symptoms are eliminated, go to one of the following: Models with Differential Pressure Feedback EGR (DPFE), go to «CIRCUIT TEST DL»(ref-23127-S03705362232001010300000) , step 50). Models with Pressure Feedback EGR (PFE), go to «CIRCUIT TEST DL»(ref-23127-S03705362232001010300000) , step 21). On all other models, go to «CIRCUIT TEST DN»(ref-23127-S05723728872001010300000) , step 42).
  4. 9) Check EGR Valve Inspect EGR valve for leaks. If valve is fully closed, go to «CIRCUIT TEST H»(ref-23127-S07532022972001010300000) , step 2). If EGR valve is leaking or is not fully seated, repair or replace valve as necessary.

Perform this test only when directed by QUICK TEST. This test is intended to diagnose

  1. Clutch Pedal Position (CPP) switch.
  2. Park/Neutral Position (PNP) switch.
  3. Powertrain Control Module (PCM).
  4. Wiring harness circuits (CPP, PNP and SIG RTN). TEST PIN WIRE COLOR IDENTIFICATION Application Wire Color TEST PIN NO. 30 (CPP/PNP) Light Blue/Yellow TEST PIN NO. 46 (SIG RTN) Gray/Red

Scheme 110

Scheme 110
Scheme 110

Scheme 111

Scheme 111
Scheme 111
  1. 1) Code 522, 525 Or 528 Code 522, 525 or 528 is a result of voltage being high at pin No. 30 (CPP/PNP input) while cranking engine or during KOEO SELF-TEST. Possible causes for these faults are: CPP or PNP circuit open. Faulty Powertrain Control Module (PCM). Starter relay disconnected during self-test. On A/T models, go to step 8). On M/T models, go to step 2).
  2. 2) Check CPP/PNP Input Turn ignition off. Turn A/C off (if equipped). Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pins No. 30 and 46 with transmission in Neutral and clutch pedal up. Also, measure resistance between test pins No. 30 and 46 with transmission in gear and clutch pedal down. If each resistance is less than 5 ohms, go to next step. If any resistance is 5 ohms or more, go to step 5). (Scheme 110): Identifying Neutral Gear/Clutch Input Circuit
  3. 3) Check CPP/PNP Switch Integrity Leave ignition off and PCM disconnected. Measure resistance between test pins No. 30 and 46 with transmission in any gear and clutch pedal up. If resistance is less than 5 ohms, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If resistance is 5 ohms or more, go to next step.
  4. 4) Check For CPP Short To Ground Leave ignition off and PCM disconnected. Disconnect CPP switch. Measure resistance between test pins No. 30 and 46. If resistance is more than 10,000 ohms, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If resistance is 10,000 ohms or less, repair short circuit. Reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000).
  5. 5) Check PNP & CPP Switches Leave ignition off and PCM disconnected. Locate PNP switch (on transmission) and CPP switch (at clutch pedal linkage). Disconnect wiring harness at both switches. Measure resistance between PNP switch terminals with transmission in Neutral. Also, measure resistance between CPP switch terminals with clutch pedal down. If each resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, replace switch. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000).
  6. 6) Check Neutral Gear/Clutch Harness Leave ignition off and PCM disconnected. Measure resistance between test pin No. 30 and the following terminals: PNP switch wiring harness connector terminal CPP and/or PNP. CPP switch wiring harness connector terminal CPP and/or PNP. Measure resistance between test pin No. 46 and the following terminals: PNP switch wiring harness connector terminal SIG RTN. CPP switch wiring harness connector terminal SIG RTN. If any resistance is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If each resistance is less than 5 ohms, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000).
  7. 7) Check CPP Switch Turn ignition and A/C off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pins No. 30 and 46 at breakout box. If resistance is less than 5 ohms, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If each resistance is 5 ohms or more, repair open circuit. Reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000).
  8. 8) Check PNP Input Turn ignition and A/C off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Ensure transmission is in Neutral or Park. Turn ignition on. Measure voltage between test pin No. 30 and chassis ground. If voltage is less than 1.0 volt, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If voltage is 1.0 volt or more, go to next step.
  9. 9) Check PNP Switch Resistance Turn ignition off. Disconnect PCM from breakout box. Disconnect PNP wiring harness connector. Measure resistance between switch terminals. If resistance is less than 5 ohms, repair open in PNP circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If resistance is 5 ohms or more, replace PNP switch. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 9) to step 15). No test procedures have been omitted.
  10. 15) Code 522: Check If Engine Starts KOEO Code 522 indicates that high voltage was sensed at test pin No. 30 during SELF-TEST. Possible causes for this fault are: Engine Starts: Transmission not in Park during SELF-TEST. Open PNP circuit between PCM and connection to START circuit. PNP/START circuit shorted to power Faulty PCM. No Start: Faulty starter relay. Open in START circuit between PNP switch and PNP connection to circuit, PNP switch and starter relay or starter relay and ground. Verify transmission was in Park during SELF-TEST. If transmission was not in Park, repeat SELF-TEST. If transmission was in Park, try to start engine. If engine starts, go to next step. If engine does not start, fault is in starter circuit. Repair as necessary.
  11. 16) Check For Short To Power In PNP/START Circuit Turn ignition off. Disconnect PCM 60-pin connector. Inspect for damage, and repair if necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Turn ignition on. Measure voltage between test pins No. 30 and 40 (GND) at breakout box. If voltage is less than 0.5 volt, turn ignition off and go to next step. If voltage is 0.5 volt or more, repair short to power. Remove breakout box and repeat «QUICK TEST»(ref-23127-S33745114692001010300000).
  12. 17) Check PNP Circuit Continuity Disconnect PNP 3-pin connector at transmission. Measure resistance between test pin No. 30 at breakout box and PNP/IGN START terminal at PNP switch vehicle wiring harness connector. If resistance is less than 5 ohms, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If resistance is 5 ohms or more, repair open circuit between PCM and PNP circuit connection to START circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). (Scheme 111): Identifying PNP/IGN START Circuit

Perform this test only when directed by QUICK TEST. This test is intended to diagnose

  1. Powertrain Control Module (PCM).
  2. Wiring harness circuits (TCIL, TCS and TCSM).

To prevent replacing good components, be aware the following non-EEC related areas may be at fault

  1. Basic engine condition (valves, vacuum leaks, valve timing, etc.).
  2. Charging system.
  3. Transmission (fluid, friction elements and cooling).

Transmission Control Switch (TCS) allows driver to disengage overdrive. TCS is located on shift plate. Mustang is equipped with a Transmission Control Switch Module (TCSM). The TCSM informs PCM of drivers request to disengage overdrive and also controls the Transmission Control Indicator Light (TCIL). TCIL is located in instrument cluster.

ApplicationWire Color
TEST PIN NO. 41 (TCS)Tan/Light Green
TEST PIN NO. 55 (TCIL)White/Light Green
TEST PIN NO. 37 OR 57 (VPWR)Red

TEST PIN WIRE COLOR IDENTIFICATION

Note. Procedure starts at step 2). No test procedures have been omitted.

  1. 2) Code 632 Or 653 Code 632 or 653 indicates that the TCS was not cycled between engine ID Code and WOT check during KOER SELF-TEST. Possible causes for this fault are: Faulty TCS or switch was not cycled during SELF-TEST. Shorted wiring harness. Faulty Powertrain Control Module (PCM). Open in wiring harness or fuse. If TCS was cycled during KOER SELF-TEST, go to step 4). If TCS was not cycled during KOER SELF-TEST, Repeat «KOER SELF-TEST»(ref-23127-S25184264992001010300000) while cycling TCS.
  2. 3) Code 623 Or 631 Code 623 or 631 indicates transmission control indicator light circuit fault during KOEO SELF-TEST. Possible causes for this fault are: Burned out bulb. Open or shorted wiring harness. If TCS was cycled during KOEO SELF-TEST, go to step 5). If TCS was not cycled during KOEO SELF-TEST, Repeat «KOER SELF-TEST»(ref-23127-S25184264992001010300000) while cycling TCS.
  3. 4) Check TCS Circuit Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 41 and test pin No. 40 or 60 at breakout box while cycling TCS several times. If voltage cycles replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If voltage does not cycle, go to next step if diagnosing a trouble code or step 20).
  4. 5) Check Circuits For Short To Ground Turn ignition off. Leave PCM disconnected from breakout box. Disconnect TCS connector. Inspect connector for damage and repair as necessary. Measure resistance between test pin No. 41 and test pin 40 or 60. Also, measure resistance between test pin No. 55 and test pin No. 40 or 60. If each reading is more than 10,000 ohms, go to next step (Code 623 or 631) or step 8) (Code 632 or 653). If any reading is 10,000 ohms or less, repair short circuit. Repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If code is still present, go to step 7).
  5. 6) Check Power Through TCIL Circuit Turn ignition off. Leave PCM disconnected from breakout box. Measure voltage between test pin No. 55 and test pin No. 40 or 60. If voltage is more than 10.5 volts, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If voltage is 10.5 volts or less, go to next step.
  6. 7) Check Output Driver Voltage Signal Leave PCM disconnected from breakout box. Turn ignition on. Measure voltage between test pin No. 55 and test pin No. 40 or 60. If voltage is 2 volts or more, go to next step. If voltage is less than 2 volts, check bulb and fuse. Replace as necessary. If bulb and fuse are okay, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  7. 8) Check Transmission Control Switch Wiring Harness Turn ignition off. Leave PCM disconnected from breakout box. Ensure TCS is disconnected. Measure resistance of Purple/Orange wire between TCS and No. 1 fuse (15-amp) at instrument panel fuse block. Measure resistance of TCS circuit between test pin No. 41 at breakout box and TCS circuit terminal at TCS wiring harness connector. If any reading is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If each reading is less than 5 ohms, go to next step.
  8. 9) Check For Short To Power Turn ignition off. Leave PCM disconnected from breakout box. Ensure TCS is disconnected. Measure resistance between test pin No. 41 and test pin No. 37 or 57. Also, measure resistance between test pin No. 55 and test pin No. 37 or 57. If each reading is more than 10,000 ohms, replace TCS switch. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If any reading is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 9) to step 20). No test procedures have been omitted.
  9. 20) Check Transmission Control Switch Module (TCSM) Turn ignition off. Leave PCM disconnected from breakout box. Remove TCSM to access wiring harness connector. TCSM is located behind right side of instrument panel. Turn ignition on. Measure voltage between Orange/Black wire and Black/White wire of TCSM connector while cycling Transmission Control Switch (TCS) several times. If voltage does not cycle, go to next step. If voltage cycles, repair open circuit between TCSM connector and PCM. If voltage cycles but Transmission Control Indicator Light (TCIL) does not turn off and on, go to step 25).
  10. 21) Check TCSM Wiring Turn ignition off. Leave PCM disconnected from breakout box. Leave TCSM connected. Turn ignition on. Measure voltage between Red/Light Green wire and Black/White wire at TCSM connector. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open circuit between ignition switch and TCSM connector. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  11. 22) Check TCSM Input From TCS Ensure ignition is on and PCM is disconnected from breakout box. Measure voltage between Tan/White wire and Black/White wire of TCSM connector while cycling TCS several times. If voltage cycles, replace TCSM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If voltage does not cycle, check TCS circuit. Repair as necessary.
  12. 23) Transmission Control Indicator Light (TCIL) Always On Turn ignition on. Cycle Transmission Control Switch (TCS) and observe TCIL. If TCIL turns off and on, problem may be intermittent. Check all TCIL related wiring and repair as necessary. Recheck TCIL operation. If TCIL does not turn off and on, go to next step.
  13. 24) Check Transmission Control Switch Module (TCSM) For Short Circuit Turn ignition off. Disconnect TCSM connector. TCSM is located behind right side of instrument panel. Turn ignition on. If TCIL is still on, repair short to ground in White/Light Green wire between TCIL and TCSM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If TCIL is off, replace TCSM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  14. 25) Transmission Control Indicator Light (TCIL) Inoperative Road test vehicle to ensure overdrive is functioning correctly. If overdrive is functioning correctly, repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If Code 631 is present, return to step 3). If Code 631 is not present, go to next step.
  15. 26) Check Voltage At Fuse Panel Turn ignition on. Remove and inspect fuse No. 15 (10-amp) at instrument panel fuse block. If fuse is blown, replace fuse and recheck TCIL operation. If fuse is okay, go to next step.
  16. 27) Check Wiring To TCSM Turn ignition off. Disconnect TCSM connector. TCSM is located behind right side of instrument panel. Connect one end of a jumper wire to ground and connect other end of jumper to White/Light Green wire at TCSM connector. Turn ignition on. If TCIL is on, problem may be intermittent. Check all TCIL related wiring and repair as necessary. Recheck TCIL operation. If TCIL light is off, check TCIL bulb. Replace bulb as necessary and recheck TCIL operation. If bulb is okay, repair open circuit between fuse block and TCSM connector. Recheck TCIL operation.

Perform this test only when directed by QUICK TEST. To prevent replacing good components, be aware the following non-EEC areas may be at fault

  1. Engine condition (compression, cam timing, valves, etc.).
  2. Charging system or battery.
  3. Transmission linkage, internal components or cooling.

This test is not intended to diagnose transmission. This test is intended to diagnose

Scheme 112

Scheme 112
Scheme 112
  1. Wiring harness circuits TCC, CCS, EPC, SS3/4, SS1, SS2, SS3, SIG RTN, EPC PWR and VPWR.
  2. Faulty Powertrain Control Module (PCM). CIRCUIT TEST TC ACRONYMS Acronym Definition CCC Converter Clutch Control CCS Coast Clutch Control EPC Electronic Pressure Control MCCC Modulated Converter Clutch Control SS Shift Solenoid TCC Torque Converter Clutch (Scheme 112): AODE Solenoid Circuits AODE DIAGNOSTIC TROUBLE CODE IDENTIFICATION Application PCM Pin No. KOEO Code EPC 38 624 & 625 SS1 51 621 SS2 52 622 TCC 53 623 & 652 TEST PIN NO. 53 (TCC) WIRE COLOR IDENTIFICATION Application Wire Color Mustang Brown/Orange
  1. 1) OUTPUT STATE CHECK Codes 621, 622, 626, 629, 641 and 652 indicates shift solenoid did not respond to PCM command. Possible causes for these faults are: Faulty solenoid assembly. Circuit open or grounded. Faulty Powertrain Control Module (PCM). To enter output state Diagnostic Test Mode (DTM), use only VOM or DVOM. DO NOT use scan tester. Turn ignition off. Disconnect cruise control servo wiring harness connector. Connect DVOM negative lead to STO terminal at Data Link Connector (DLC). Connect positive lead to positive battery terminal. Connect a jumper wire between SIG RTN terminal and STI terminal at DLC. (Scheme 108) Perform «KOEO SELF-TEST»(ref-23127-S30488885572001010300000) until continuous memory test is complete. DVOM will read less than 1.0 volt when test is complete to indicate PCM has entered output state DTM. Depress and release throttle. If voltage increases, remain in output state DTM and go to next step. If voltage does not increase, depress throttle to WOT and release. If STO voltage goes high, go to next step. If STO voltage does not go high, leave test equipment connected and go to «CIRCUIT TEST QC»(ref-23127-S34551617272001010300000).
  2. 2) Check Solenoid Electrical Condition Turn ignition off. Disconnect transmission wiring harness connector. Inspect terminals, and repair if damaged. Connect VOM or DVOM positive test lead to solenoid wiring harness connector VPWR terminal. Connect negative test lead to appropriate shift solenoid terminal at transmission wiring harness connector. Turn ignition on. Cycle solenoid output on and off by depressing and releasing throttle 3-5 times. If voltage output changes 0.5 volt or more, fault is in transmission. If voltage output does not change 0.5 volt or more, remove jumper wire between SIG RTN terminal and STI terminal at DLC. Go to next step.
  3. 3) Check Solenoid & VPWR Circuit Continuity Turn ignition off. Leave transmission wiring harness disconnected. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between suspect signal output terminal at transmission vehicle wiring harness connector terminal and corresponding test terminal at breakout box. See appropriate wiring schematic at beginning of this circuit test. Also, measure resistance between breakout box test pins No. 37 and 57 and VPWR terminal at transmission vehicle wiring harness connector. If each resistance is less than 5 ohms, go to next step. If any resistance is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000).
  4. 4) Check Solenoid Circuit For Short To Power Or Ground Leave ignition off and PCM disconnected. Leave transmission wiring harness disconnected. Measure resistance between suspect solenoid output signal test pin and test pins No. 37 and 57 at breakout box. Also, measure resistance between suspect solenoid output signal test pin and pins No. 40, 46 and 60 at breakout box and chassis ground. Measure resistance between PCM output signal test pin and chassis ground. If any reading is less than 10,000 ohms, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If all readings are 10,000 ohms or more, check solenoids. If solenoids are okay, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 4) to step 10). No test procedures have been omitted.
  5. 10) Code 624 Or 625: Check VPWR To Solenoid Code 624 indicates failure of EPC circuit. Code 625 indicates EPC driver failure. Possible causes for these faults are: Faulty solenoid. Circuit open or grounded. Turn ignition off. Disconnect transmission wiring harness connector. Turn ignition on. Measure voltage between VPWR and EPC PWR terminal at transmission wiring harness connector and chassis/battery ground. If voltage is less 10.5 volts or less, repair open circuit. Reconnect all components and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If voltage is more than 10.5 volts, go to next step.
  6. 11) Check Solenoid Signal & VPWR Circuit Continuity Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between VPWR/EPC PWR terminal at transmission wiring harness connector breakout box test pins No. 37 and 57. Also, measure resistance between test pin No. 38 at breakout box and EPC terminal at transmission wiring harness connector. If resistance is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If resistance is less than 5 ohms, go to next step.
  7. 12) Check Circuit For Short To Power Or Ground Leave ignition off and PCM disconnected. Leave transmission wiring harness connector disconnected. Measure resistance between test pins No. 37 and 57 and suspect solenoid test pin at breakout box. Also, measure resistance between test pins No. 40, 46 and 60 and suspect solenoid test pin at breakout box. If any reading is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If all readings are more than 10,000, check solenoids. If solenoids are okay, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 12) to step 20). No test procedures have been omitted.
  8. 20) Code 621, 622, 641 Or 643: Check Solenoid Resistance KOEO Code 621 (SS1), 622 (SS2), 641 (SS3) or 643 (TCC) indicate failure in shift solenoid circuit. Possible causes for these faults are: Faulty shift solenoid. Circuit open or grounded. Faulty PCM. Turn ignition off. Disconnect transmission wiring harness connector. Measure resistance between suspect shift solenoid at transmission wiring harness connector and chassis ground. If resistance is 13-27 ohms, go to next step. If resistance is not 13-27 ohms, go to step 25).
  9. 21) Check Shift Solenoid For Short To Power Leave ignition off and transmission wiring harness connector disconnected. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Turn ignition on. Measure voltage between suspect shift solenoid at transmission wiring harness connector and chassis ground. If voltage is 0.5 volt or more, repair short to power and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If voltage is less than 0.5 volt, go to next step.
  10. 22) Check Shift Solenoid For Short To Ground Turn ignition off. Leave transmission wiring harness connector disconnected. Measure resistance between suspect shift solenoid at transmission wiring harness connector and chassis ground. Also, measure resistance between suspect shift solenoid and other circuits at transmission wiring harness connector. If any reading is 10,000 ohms or less, repair short circuit. Reconnect all components and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If all readings are more than 10,000 ohms, go to next step.
  11. 23) Check Shift Solenoid Circuit Continuity Turn ignition off. Leave transmission wiring harness connector disconnected. Install EEC-IV Breakout Box (T83L-50-EEC-IV) or 4EAT tester, leaving PCM disconnected. Measure resistance between suspect shift solenoid test pin at breakout box and suspect shift solenoid terminal at transmission wiring harness connector. If resistance is 5 ohms or more, repair open circuit. Reconnect all components and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If resistance is less than 5 ohms, go to next step.
  12. 24) Check Shift Solenoid For Short To Power In Transmission Leave ignition off and PCM disconnected. Reconnect transmission wiring harness connector. Measure voltage between test pin No. 60 and suspect shift solenoid test pin at breakout box. If voltage is 0.5 volt or more, replace or repair solenoid for a short to power (within transmission). Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If voltage is less than 0.5 volt, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000).
  13. 25) Check Transmission Wiring Leave ignition off. Check transmission wiring harness circuits and connectors breaks or corrosion in insulation. Check for open or grounded circuits. Repair or replace wiring as necessary. If connectors and circuits are okay, replace suspect solenoid and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 25) to step 30). No test procedures have been omitted.
  14. 30) Continuous Memory Codes 621, 622, 641 & 643 Continuous Memory Code 621 (SS1), 622 (SS2), 641 (SS3) or 643 (TCC) indicates a failure was detected in shift solenoid circuit during last 80 warm-up cycles. Possible causes for these faults are: Faulty shift solenoid. Circuit open or grounded. Turn ignition off. Check shift solenoid circuit between PCM and transmission. Repair or replace wiring as necessary. If circuits are okay, go to next step.
  15. 31) Check For Intermittent Short Or Open Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV) or 4EAT tester, leaving PCM disconnected. Turn ignition on. Connect test light between test pin No. 37 and suspect shift solenoid test pin at breakout box. See «IDENTIFYING SHIFT SOLENOID TEST CIRCUITS»(ref-23127-S40605078572001010300000) table. Test light should be at partial brightness. Observe test light while wiggling and bending shift solenoid circuit between transmission and PCM. An open or short to power will be indicated by light going off. A short to ground will be indicated by light getting brighter. Repeat procedure for all solenoids. If fault is indicated, isolate and repair as necessary. If no fault is indicated, go to next step. IDENTIFYING SHIFT SOLENOID TEST CIRCUITS Shift Solenoid Test Pin No. SS1 11 SS2 51 SS3 52 CCC 55
  16. 32) Check For Intermittent Short To Ground Leave ignition off and PCM disconnected. Disconnect transmission wiring harness connector. Turn ignition on. Connect test light between test pin No. 37 and suspect shift solenoid test pin at breakout box. See «IDENTIFYING SHIFT SOLENOID TEST CIRCUITS»(ref-23127-S40605078572001010300000) table. Test light should be off. Observe test light while wiggling and bending shift solenoid circuit between transmission and PCM. A short to ground will be indicated by light turning on. Repeat procedure for all solenoids. If fault is indicated, isolate and repair as necessary. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If no fault is indicated, problem is intermittent and cannot be duplicated at this time.

Perform this test only when directed by QUICK TEST. To prevent replacing good components, be aware the following non-EEC areas may be at fault

  1. Transmission linkage and internal components.
  2. Electrical (alternator, battery, add-on devices, etc.).

This test is not intended to diagnose transmission. This test is intended to diagnose

  1. Wiring harness circuits TR, TRD, TRL, TRR, TROD and SIG RTN.
  2. Powertrain Control Module (PCM).

Transmission range sensor may also be known as transmission range switch.

Identifying TR Sensor Circuits (AODE). Scheme 113

Scheme 113: Identifying TR Sensor Circuits (AODE)
Scheme 113: Identifying TR Sensor Circuits (AODE)
  1. 1) Codes 522, 634, 654, 667 & 668: Check TR Sensor Alignment KOEO Code 634 indicates TR sensor is out of self-test range (3770-4607 ohms) when gear selector is in Park position. KOEO Codes 522 and 654 indicate gear selector was not in Park position during self-test. KOEO Code 667 indicates a short to ground in TR sensor circuits. KOEO Code 668 indicates an open in TR sensor circuits. Possible causes for these faults are: Transmission range not in Park during SELF-TEST. Linkage not adjusted correctly. Faulty TR sensor. Circuit open or shorted. Faulty Powertrain Control Module (PCM). Turn ignition off. Apply parking brake. Check TR sensor adjustment. Adjust sensor as necessary. See ADJUSTMENTS in the TRANSMISSION SERVICING - A/T article. If sensor is adjusted properly, go to next step.
  2. 2) Check TR Sensor Circuit Continuity Turn ignition off. Disconnect TR sensor wiring harness connector. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between TR terminal at TR sensor wiring harness connector and test pin No. 30 at breakout box. Also, measure resistance between SIG RTN terminal at TR sensor wiring harness connector and test pin No. 46 at breakout box. If any reading is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If both readings are less than 5 ohms, go to next step.
  3. 3) Check TR Sensor For Short To Power & Ground Turn ignition off. Leave PCM and TR sensor disconnected. Measure resistance between test pin No. 30 and test pins No. 37, 40, 46, 57 and 60 at breakout box. Also, measure resistance between test pin No. 30 and chassis ground. If any reading is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If resistance is more than 10,000 ohms, go to next step.
  4. 4) Check TR Sensor Resistance Turn ignition off. Connect TR sensor. Leave PCM disconnected. Unlock steering column. Measure resistance between test pins No. 30 and 46 at breakout box while cycling gear selector. See «TR SENSOR RESISTANCE»(ref-23127-S23203438752001010300000) table. If resistance is within specification, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If resistance is not within specification, replace TR sensor and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . TR SENSOR RESISTANCE Gear Selected Ohms Park 3770-4607 Reverse 1304-1593 Neutral 660-807 Overdrive 361-442 Drive 190-232 First 78-95 NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 4) to step 9). No test procedures have been omitted.
  5. 9) Transmission In Third Gear Only While in D/OD Ensure transmission fluid is at correct level and in good condition. Test drive vehicle with shift lever in both D and OD positions. If transmission always remains in 3rd gear when vehicle is operated with shift lever in D or OD position, go to step 11). If transmission sometimes shifts okay, go to step 20).
  6. 10) Continuous Memory Code 634 Code 634 indicates PCM has received incorrect voltage signals from PNP switch. Test drive vehicle with shift lever in both D and OD positions. If transmission always remains in 3rd gear when vehicle is operated with shift lever in D or OD position, go to next step. If transmission sometimes shifts okay, go to step 20).
  7. 11) Check IGN START/RUN Circuit At Transmission Turn ignition off. Disconnect 4EAT wiring harness connector at transmission. Turn ignition on. Measure voltage between IGN START/RUN terminal at transmission wiring harness connector and chassis ground. If voltage is 10.5 volts or less, repair open circuit and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If voltage is more than 10.5 volts, go to next step.
  8. 12) Check Transmission Select Switches Leave ignition off and 4EAT wiring harness connector disconnected. Disconnect 3-pin inhibit (PNP) switch connector at transmission. Check that each switch state resistance is correct for each gear selector position. If any resistance is not correct, go to step 14). If all resistances are correct, go to next step.
  9. 13) Check Transmission Switch Input Voltage Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV) or 4EAT tester, leaving PCM disconnected. Reconnect inhibit switch and transmission switch connectors. Turn ignition on. Check that each switch state voltage at breakout box is correct for each gear selector position. If all voltage readings are correct and no other problems can be found, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If any voltage reading is not correct, repair circuit(s) and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  10. 14) Check TR Sensor & Wiring Turn ignition off. Check TR sensor circuits and connectors for damage and corrosion. Repair wiring as necessary. If wiring is okay, ensure TR sensor is adjusted correctly. Adjust sensor as necessary. See ADJUSTMENTS in the TRANSMISSION SERVICING - A/T article. If sensor is adjusted properly, replace TR sensor. Reconnect all components and check system operation. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 14) to step 20). No test procedures have been omitted.
  11. 20) Inspect 4EAT Circuit Turn ignition off. Inspect TR sensor and transmission shift solenoid wires between PCM and transmission for corrosion or damage. Inspect wiring harness for correct routing. If any faults are found, repair or replace as necessary. If no faults are found, go to next step.
  12. 21) Check Wiring Harness & Connectors For Intermittent Open Or Short Circuit Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV) or 4EAT tester, leaving PCM disconnected. Turn ignition on. Connect test light between test pin No. 40 and transmission test pin as follows: Test pin No. 18 (TRD) with gear selector in D. Test pin No. 23 (TRR) with gear selector in R. Test pin No. 38 (TROD) with gear selector in OD. Test pin No. 45 (TRL) with gear selector in L. Test light should be on when gear selector is in the same gear as the circuit being tested. Shake and wiggle transmission switch wiring harness between PCM and transmission. Lightly tap on inhibit switch to simulate road shock. If test light dims, flickers or goes off, fault is indicated. Isolate fault and repair as necessary. Remove breakout box, reconnect all components and check system operation. If test light stays on, fault cannot be duplicated at this time. CAUTION: Following road test is an optional procedure. Follow all applicable safety procedures and traffic laws. This road test requires a driver and an assistant. Assistant should make measurements, observe changes and record notes. If this test is not performed, go to the «H - TESTS W/O CODES - EEC-IV (5.0L)»(ref-23230) article for other possible causes.

Perform this test only when directed by QUICK TEST. To prevent replacing good components, be aware the following non-EEC areas may be at fault

  1. Engine and/or transmission fluid level.
  2. Engine and/or transmission fluid temperature.
  3. Ambient temperature.

This test is intended to diagnose

Scheme 114

Scheme 114
Scheme 114
  1. TFT sensor.
  2. Wiring harness circuits TFT and SIG RTN.
  3. Faulty Powertrain Control Module (PCM). (Scheme 114): Transmission Fluid Temperature (TFT) Sensor Circuit TFT SENSOR SPECIFICATIONS Temperature °F (°C) (1) Volts (1) Ohms 32 (0) 3.88 96,255 59 (15) 3.32 46,883 104 (40) 2.15 16,043 158 (60) 1.03 5260 194 (90) 0.60 2750 (1) Values may vary by 15 percent.
  1. 1) KOEO Code 636 KOEO Code 636 indicates TFT sensor is out of self-test range. Possible causes for these faults are: Transmission fluid level incorrect. Transmission fluid temperature incorrect. Sensor resistance out of specification. Faulty Powertrain Control Module (PCM). Ensure transmission fluid temperature is more than 50°F (10°C). Repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If Code 636 is present, go to next. If Code 636 is not present, no problem is indicated at this time. Test is complete.
  2. 2) Check VREF At Throttle Position (TP) Sensor Turn ignition off. Disconnect TP sensor wiring harness connector. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Turn ignition on. Measure voltage between VREF and SIG RTN terminals at TP sensor wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to «CIRCUIT TEST C»(ref-23127-S13417218072001010300000) .
  3. 3) Check TFT Sensor Resistance Turn ignition off. Disconnect PCM from breakout box. Allow transmission to cool. Measure and record resistance between test pin No. 46 and TFT test pin at breakout box. Reconnect PCM. Drive vehicle until transmission fluid is normal operating temperature. Disconnect PCM from breakout box. Again, measure resistance between test pin No. 46 and TFT test pin at breakout box. If cold resistance measurement is greater than warm resistance measurement, and warm resistance is within specification, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . See «TFT SENSOR SPECIFICATIONS»(ref-23127-S20693356992001010300000) table at beginning of this circuit test. If resistance is not as specified, service TFT sensor. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 10). No test procedures have been omitted.
  4. 10) KOEO Code 637 KOEO Code 637 indicates TFT sensor output exceeds self-test maximum voltage (4.8 volts). Possible causes for these faults are: Transmission fluid level incorrect. Open wiring harness circuit. Faulty TFT sensor. Faulty PCM. Turn ignition off. Disconnect transmission connector. Inspect terminals, and repair if damaged. Connect jumper wire between TFT and SIG RTN terminals at transmission vehicle wiring harness connector. Perform «KOEO SELF-TEST»(ref-23127-S30488885572001010300000) . If Code 638 is present, remove jumper wire and service TFT sensor. If Code 638 is not present, remove jumper wire and go to next step.
  5. 11) Check TFT & SIG RTN Circuit Continuity Turn ignition off. Leave transmission connector disconnected. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between TFT circuit at transmission vehicle wiring harness connector and TFT test pin at breakout box. Also, measure resistance between SIG RTN circuit at transmission vehicle wiring harness connector and test pin No. 46 at breakout box. If any reading is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If all readings are less than 5 ohms, go to next step.
  6. 12) Check TFT Sensor For Short To VPWR Turn ignition off. Leave PCM and transmission connector disconnected. Measure resistance between TFT test pin and test pins No. 37 and 57 at breakout box. If all readings are more than 10,000 ohms, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If any reading is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 12) to step 20). No test procedures have been omitted.
  7. 20) KOEO Code 638 KOEO Code 638 indicates TFT sensor output is lower than self-test minimum voltage. Possible causes for these faults are: Damaged TFT sensor. Shorted wiring harness circuit. Faulty PCM. Turn ignition off. Disconnect transmission wiring harness connector. Inspect terminals, and repair if damaged. Perform «KOEO SELF-TEST»(ref-23127-S30488885572001010300000) with transmission connector disconnected. If Code 637 is present, service TFT sensor. If Code 637 is not present, go to step 21).
  8. 21) Check VREF At Throttle Position (TP) Sensor Turn ignition off. Disconnect TP sensor wiring harness connector. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Turn ignition on. Measure voltage between VREF and SIG RTN terminals at TP sensor vehicle wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to «CIRCUIT TEST C»(ref-23127-S13417218072001010300000) .
  9. 22) Check TFT Circuit For Short To Ground Turn ignition off. Disconnect PCM from breakout box. Measure resistance between TFT test pin at breakout box and test pins No. 40, 46 and 60. If all readings are more than 10,000 ohms, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If any reading is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 25). No test procedures have been omitted.
  10. 25) Check Transmission Wiring Harness Turn ignition off. Check transmission internal and external wiring and connectors for damage and corrosion. Repair or replace as necessary and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If wiring is okay, replace TFT sensor and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 25) to step 90). No test procedures have been omitted.
  11. 90) Continuous Memory Code 637 Or 638 Continuous Memory Code 637 or 638 indicates a fault has been detected in TFT circuit during previous 80 warm-up cycles. Possible causes for these faults are: Incorrect fluid level. Intermittent fault in TFT sensor. Intermittent short or open in wiring harness. Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Connect DVOM between test pins No. 2 and 46 at breakout box. Turn ignition on. Note DVOM voltage reading. Shake and bend TFT and SIG RTN wires between transmission and PCM. Voltage should remain stable or change gradually. If voltage drops to zero, a short to ground is indicated. If voltage increases up to 5 volts, an open circuit is indicated. If voltage increases to more than 5 volts, a short to power is indicated. If fault is indicated, isolate and repair as necessary. If no faults are found, go to «CIRCUIT TEST TD»(ref-23127-S17193677512001010300000) , step 22). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 90) to step 100). No test procedures have been omitted.
  12. 100) Continuous Memory Code 657 Continuous Memory Code 657 indicates excessive transmission temperatures. Possible causes for these faults are: Damage in transmission cooling system. Pulling overweight trailer. Incorrect fluid level. Damaged clutch. Fault in TFT sensor. Intermittent short or open in wiring harness. Turn ignition off. Disconnect transmission wiring harness connector. Inspect terminals, and repair if damaged. Reconnect transmission connector. Perform «KOEO SELF-TEST»(ref-23127-S30488885572001010300000) . If no code(s) is present, fault is in transmission. If Code 657 is present, fault is in transmission. If any other code(s) is present, service as necessary and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .

Perform this test only when directed by QUICK TEST. This test is intended to diagnose

  1. Wiring harness circuit TSS.
  2. Faulty Powertrain Control Module (PCM).

The TSS is a magnetic pickup that sends a signal to PCM. Sensor is mounted on transmission.

Identifying Turbine Shaft Speed Sensor Circuit. Scheme 115

Scheme 115: Identifying Turbine Shaft Speed Sensor Circuit
Scheme 115: Identifying Turbine Shaft Speed Sensor Circuit
ApplicationWire Color
TEST PIN NO. 5 (TSS)Dark Green/White

TEST PIN WIRE COLOR IDENTIFICATION

Scheme 116

Scheme 116
Scheme 116
  1. 1) KOER Code 639 KOER Code 639 indicates input from TSS to PCM is out of calibration. Possible causes for this fault are: Faulty TSS. Circuit open or grounded. Faulty Powertrain Control Module (PCM). Turn ignition off. Disconnect TSS wiring harness connector. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between TSS (+) terminal at TSS wiring harness connector and test pin No. 5 at breakout box. Also, measure resistance between SIG RTN terminal at TSS wiring harness connector and test pin No. 46 at breakout box. If any reading is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If both readings are less than 5 ohms, go to next step.
  2. 2) Check Circuit For Short To Power Or Ground Leave ignition off and TSS disconnected. Measure resistance between test pin No. 5 and test pins No. 37 and 57 at breakout box. Measure resistance between test pin No. 5 and test pins No. 40, 46 and 60 at breakout box (some models may have a 4700-ohm resistor to ground). If any reading is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If all readings are more than 10,000 ohms, go to next step.
  3. 3) Measure TSS Resistance Leave ignition off and TSS disconnected. Measure resistance between TSS terminals. Resistance should be 450-750 ohms. If resistance is not as specified, replace TSS and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If resistance is as specified, check internal transmission components. If transmission is okay, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). TRANSMISSION IDENTIFICATION Application Transmission Mustang AODE NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 10). No test procedures have been omitted.
  4. 10) Code 639: Check TSS Resistance Code 639 indicates incorrect input signal from TSS. Possible causes for this fault are: Faulty TSS. Circuit open or grounded. Faulty PCM. Turn ignition off. Disconnect transmission 12-pin connector. Measure resistance between TSS (-) and TSS (+) terminal at transmission connector. (Scheme 116) If resistance is not 200-600 ohms, check wiring for damage and corrosion. If wiring is okay, replace TSS and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If resistance is 200-600 ohms, go to next step. (Scheme 116): Identifying Transmission 12-Pin Connector Terminals
  5. 11) Check TSS Circuit For Short To Power Leave ignition off and transmission 12-pin connector disconnected. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Turn ignition on. Measure voltage between chassis ground and TSS (+) terminal at transmission vehicle wiring harness connector. Also, measure voltage between chassis ground and TSS (-) terminal at transmission vehicle wiring harness connector. If both readings are less than 0.5 volt, go to next step. If any reading is 0.5 volt or more, repair short circuit. Reconnect all components and repeat «QUICK TEST»(ref-23127-S33745114692001010300000).
  6. 12) Turn ignition off. Leave transmission connector and PCM disconnected. Measure resistance between chassis ground and TSS (+) terminal at transmission vehicle wiring harness connector. Measure resistance between chassis ground and TSS (-) terminal at transmission vehicle wiring harness connector. Also, measure resistance between TSS (+) terminal and TSS (-) terminal at transmission vehicle wiring harness connector. If any reading is 10,000 ohms or less, repair short circuit and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If all readings are more than 10,000 ohms, go to next step.
  7. 13) Check TSS Circuit Continuity Leave ignition off and transmission 12-pin connector disconnected. Install EEC-IV Breakout Box (T83L-50-EEC-IV) or 4EAT tester, leaving PCM disconnected. Measure resistance between TSS (+) terminal at transmission vehicle wiring harness connector and test pin No. 24 at breakout box. Also, measure resistance between TSS (-) terminal at transmission vehicle wiring harness connector and test pin No. 44 at breakout box. If any reading is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If both readings are less than 5 ohms, go to next step.
  8. 14) Check PCM For Internal Shorts Turn ignition off. Connect PCM to breakout box. Leave transmission wiring harness connector disconnected. Measure resistance between test pin No. 24 and pins No. 37, 40, 44, 57 and 60 at breakout box. If any reading is 500 ohms or less, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If all readings are more than 500 ohms, go to next step.
  9. 15) Check TSS Output Turn ignition off. Leave PCM connected to breakout box. Reconnect transmission 12-pin connector. Set DVOM on AC voltage scale. Start engine. Measure voltage between breakout box test pins No. 24 and 44 while varying engine speed. If AC voltage varies more than 0.5 volt, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If AC voltage does not vary more than 0.5 volt, replace TSS. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 15) to step 90). No test procedures have been omitted.
  10. 90) Continuous Memory Code 639 Code 639 indicates PCM detected incorrect output signal from TSS during previous 80 warm-up cycles. Possible causes for this fault are: Faulty TSS. Faulty transmission. Circuit open or grounded. Faulty PCM. Record and clear continuous memory codes. Warm engine to normal operating temperature. While test driving vehicle, stop, ensure transmission gear selector is in Drive position and accelerate heavily to 35 MPH. After test drive, perform QUICK TEST and record all codes. If Continuous Memory Code 639 does not repeat, problem cannot be duplicated at this time. If Continuous Memory Code 639 is repeated, go to next step.
  11. 91) Check TSS Circuit Continuity Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect TSS wiring harness connector. Measure resistance between TSS terminal at TSS vehicle wiring harness connector and test pin No. 5 at breakout box. Also, measure resistance between SIG RTN terminal at TSS vehicle wiring harness connector and test pin No. 46 at breakout box. If any reading is 5 ohms or more, repair open circuit. Repeat step 90) to verify code elimination. If both readings are less than 5 ohms, go to next step.
  12. 92) Check Circuit For Short To Power Or Ground Turn ignition off. Leave TSS disconnected. Measure resistance between test pin No. 5 and test pins No. 37 and 57 at breakout box. Also, measure resistance between test pin No. 5 and test pins No. 40, 46 and 60 at breakout box. If any reading is 500 ohms or less, repair short circuit. Repeat step 90) to verify code elimination. If both readings are more than 500 ohms, go to next step.
  13. 93) Measure TSS Sensor Resistance Turn ignition off. Leave sensor disconnected. Measure resistance between sensor terminals. On models with AODE transmission, resistance should be 450-750 ohms. See «TRANSMISSION IDENTIFICATION»(ref-23127-S39590277352001010300000) table. On models with AX4S, AX4N or CD4E transmission, resistance should be 80-300 ohms. If resistance as specified, check internal transmission components and repair as necessary. If transmission is okay, replace PCM and repeat step 90) to verify code elimination. If resistance is not as specified, replace sensor and repeat step 90) to verify code elimination. TRANSMISSION IDENTIFICATION Application Transmission Mustang AODE NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 93) to step 95). No test procedures have been omitted.
  14. 95) Continuous Memory Code 639: Check TSS Wiring Continuous Memory Code 639 indicates an error in TSS sensor output during previous 80 warm-up cycles. Possible causes for this fault are: Intermittent fault in TSS. Intermittent short or open in wiring harness. Transmission placed in gear when fluid level is low. Turn ignition off. Visually inspect TSS wires and connectors for damage. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Connect DVOM between test pins No. 24 and 44 at breakout box. Start engine. Observe DVOM and perform the following. Shake and bend TSS wires between transmission and PCM. Lightly tap circuit connectors. Voltage should remain stable or change gradually. If voltage drops or surges abruptly, fault in circuit is indicated. If fault is indicated, isolate fault and repair as necessary. If no faults are found, go to next step.
  15. 96) Check PCM & Harness Connectors Turn ignition off. Disconnect all connectors related to TSS circuit. Inspect circuits and connectors for damage. Repair as necessary. Reconnect all connectors and repeat «QUICK TEST»(ref-23127-S33745114692001010300000). If fault cannot be found, problem is intermittent and cannot be duplicated at this time. Go to next step. CAUTION: Following road test is an optional procedure. Follow all applicable safety procedures and traffic laws. This road test requires a driver and an assistant. Assistant should make measurements, observe changes and record notes. If this test is not performed, go to «H - TESTS W/O CODES - EEC-IV (5.0L)»(ref-23230) article for other possible causes.

Drive vehicle to create conditions so that symptom will occur. Information provided by vehicle operator may help when trying to recreate symptom. When symptom occurs, assistant should observe and record changes in voltage signals.

Information about symptom, operating condition value of voltage signal and any other information available should be recorded for analysis. After test is completed, analyze results to locate and repair fault causing symptom. If problem cannot be identified, go to the H - TESTS W/O CODES - EEC-IV (5.0L) article for other possible causes of symptom.

Perform this test only when directed by QUICK TEST. To prevent replacing good components, be aware the following non-EEC areas may be at fault

  1. Transmission fluid level.
  2. Engine/transmission fluid temperature.
  3. Ambient temperature.
  4. Aftermarket modifications.
  5. Engine sensors.
  6. Faulty wiring harness connectors.

This test is intended to diagnose

Scheme 117

Scheme 117
Scheme 117
  1. Wiring harness circuits CCS, SS1, SS2, SS3, EPC, TCC, TFT, TR and 3-2/CC3.
  2. Powertrain Control Module (PCM) (Scheme 117): Identifying A0DE Electronic Transmission Circuits TEST PINS NO. 30 (TR) & 53 (TCC) WIRE COLOR ID Application Test Pin No. Wire Color Mustang 53 Purple/Yellow Mustang 30 Light Blue/Yellow NOTE: Procedure begins with step 90). No test procedures have been omitted.
  1. 90) Perform Drive Cycle Test Ensure all components are connected. Ensure transmission fluid is correct level. Warm engine to normal operating temperature. Perform «KOEO SELF-TEST»(ref-23127-S30488885572001010300000) and CONTINUOUS MEMORY CODE SELF-TEST. Clear all codes. Perform «DRIVE CYCLE TEST»(ref-23127-S10823947342001010300000) .
  2. 91) Code 624, 634 Or 651 Code 624 and 651 indicate Electronic Pressure Control (EPC) failure. Code 634 indicates that Transmission Range (TR) sensor is out of calibration. Possible causes for these faults are: Faulty EPC solenoid. Faulty TR sensor. Circuit open or grounded. Damaged PCM connector pins. Turn ignition off. Disconnect 60-pin PCM connector. Inspect connector for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. To test EPC solenoid, connect DVOM between EPC test pin and EPC VPWR test pin at breakout box. To test TR sensor, connect DVOM between TR test pin and test pin No. 46 at breakout box. For EPC solenoid or TR sensor, turn ignition on. Voltage for EPC should be less than 10 volts. Voltage for TR should be less than 5 volts with transmission in Park. Shake and bend EPC/TR wiring harness. Lightly tap on components to simulate road shock. Voltage should remain stable. If voltage changes or exceeds specification, fault in circuit is indicated. If fault is indicated, isolate fault and repair as necessary. Clear continuous memory codes, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If no faults are found, problem cannot be located at this time.
  3. 92) Check Circuit Harness & Connectors Enter CONTINUOUS MONITOR MODE. Shake and bend EEC wiring harness while observing analog VOM or scan tool. Lightly tap on components to simulate road shock. If VOM indicator has erratic movement or scan tool beeps, fault is indicated. If fault is indicated, isolate and repair as necessary. Clear continuous memory codes, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If no faults are found, problem cannot be located at this time. CIRCUIT TEST KOEO CONTINUOUS MEMORY CODES Code Fault 617 Improper 1-2 Shift 618 Improper 2-3 Shift 619 Improper 3-4 Shift 628 Excessive Converter Clutch Slippage 637 Excessive TFT Circuit Voltage 638 Inadequate TFT Circuit Voltage 645 Inadequate 1st Gear Command Response 646 Inadequate 2nd Gear Command Response 647 Inadequate 3rd Gear Command Response 648 Inadequate 4th Gear Command Response 656 Continuous Slippage Detected
  4. 93) Check For Code 659 Code 659 indicates high vehicle speed detected while vehicle was in Park. Possible causes for this fault are: Faulty Transmission Range (TR) sensor. Faulty Powertrain Control Module (PCM). If Code 659 was present after performing drive cycle test in step 90), go to step 103). If Code 659 was not present after performing drive cycle test in step 90), go to next step.
  5. 94) Check For Code 675 Code 675 indicates TR circuit voltage was out of range. Possible causes for this fault are: Faulty TR sensor. Open or short circuit. Short to power or ground in SIG RTN circuit. Faulty Powertrain Control Module (PCM). If Code 675 was present after performing drive cycle test in step 90), go to next step. If Code 675 was not present after performing drive cycle test in step 90), go to step 98).
  6. 95) Check For Codes 675 & 667 Code 667 indicates TR circuit voltage was less than self-test minimum voltage allowed. Possible causes for this fault are: Faulty TR sensor. Open or short in TR circuit. Short to power in TR circuit. Faulty Powertrain Control Module (PCM). If Codes 675 and 667 were present after performing drive cycle test in step 90), go to step 99). If Codes 675 and 667 were not present after performing drive cycle test in step 90), go to next step.
  7. 96) Check For Codes 675 & 668 Code 668 indicates TR circuit voltage was more than self-test maximum voltage allowed. Possible causes for this fault are: Faulty TR sensor. Open TR circuit. Short to power in SIG RTN circuit. Faulty Powertrain Control Module (PCM). If Codes 675 and 668 were present after performing drive cycle test in step 90), go to step 101). If Code 675 and 668 were not present after performing drive cycle test in step 90), go to next step.
  8. 97) Check TR Alignment Turn ignition off. Apply parking brake. Place transmission gear selector in Neutral position. Check TR sensor adjustment. See ADJUSTMENTS in the TRANSMISSION SERVICING - A/T article. Adjust sensor as necessary, clear codes and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If sensor is adjusted properly, go to next step.
  9. 98) Check For Code 667 Code 667 indicates TR circuit voltage less than self-test minimum voltage allowed. Possible causes for this fault are: Faulty TR sensor. Open or short to ground in TR circuit. Faulty Powertrain Control Module (PCM). If Code 667 was present after performing drive cycle test in step 90), go to next step. If Code 667 was not present after performing drive cycle test in step 90), go to step 101).
  10. 99) Check TR Circuit Resistance Turn ignition off. Disconnect 60-pin PCM connector. Disconnect TR sensor. Inspect connectors for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pin No. 30 at breakout box and TR terminal at TR sensor connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  11. 100) Check For Shot To Ground In TR Circuit Turn ignition off. Ensure breakout box is installed and TR sensor and PCM are disconnected. Measure resistance between test pin No. 30 and chassis ground. If resistance is more than 10,000 ohms, go to step 103). If resistance is 10,000 or less, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  12. 101) Code 668 Code 668 indicates TR circuit voltage was more than self-test maximum voltage allowed. Possible causes for this fault are: Faulty TR sensor. Open TR circuit. Faulty TR sensor circuit. Faulty Powertrain Control Module (PCM). Turn ignition off. Disconnect 60-pin PCM connector. Disconnect TR sensor. Inspect connectors for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pins No. 46 at breakout box and SIG RTN terminal at TR sensor connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  13. 102) Check For Short To Power Ensure PCM and TR sensor are disconnected. Measure resistance between test pin No. 30 and test pins No. 37, 40, 46, 57 and 60 at breakout box. If all readings are more than 10,000 ohms, go to next step. If any reading is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) .
  14. 103) Check TR Sensor Resistance Turn ignition off. Connect TR sensor. Leave PCM disconnected. Unlock steering column. Measure resistance between test pins No. 30 and 46 at breakout box while cycling gear selector. See «TR SENSOR RESISTANCE»(ref-23127-S04599148982001010300000) table. If resistance is within specification, replace PCM and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . If resistance is not within specification, replace TR sensor and repeat «QUICK TEST»(ref-23127-S33745114692001010300000) . TR SENSOR RESISTANCE Gear Selected Ohms Park 3770-4607 Reverse 1304-1593 Neutral 660-807 Overdrive 361-442 2/Drive 190-232 First 78-95