Diagnosis - E4OD: Other Ford Bronco V

Air Conditioning Clutch (ACC)

On factory installed A/C system, PCM receives signal voltage from ACC switch indicating that the air conditioning compressor clutch is engaged. The PCM uses the ACC switch signal to adjust line pressure to compensate for additional engine load. If the ACC switch fails with closed contacts, line pressure will be slightly low with air conditioning off. If the ACC switch fails with open contacts, line pressure will be slightly high with air conditioning on.

Brake On/Off (BOO) Switch

The PCM receives a signal from the BOO switch when the brake switch is operated. Torque converter clutch is disengaged when brakes are applied. Malfunctioning switch will affect torque converter operation.

4WD Low Switch

Low range switch is located on transfer case cover. Switch modifies shift schedule for 4WD transfer case gear ratio. Early shifts will occur if switch fails in ON position. Delayed shifts will occur if switch fails in OFF position.

Mass Airflow Sensor (MAS)

The MAS signal is used for Electronic Pressure Control (EPC), shift and TCC scheduling. Sensor malfunction will affect shift and TCC scheduling.

Manual Lever Position (MLP)

The PCM monitors a series of step down resistors in the MLP sensor that act as a voltage divider. The voltage signal corresponds with position of the transmission range selector lever. The MLP sensor also contains the neutral/start and backup circuits. Malfunction of the MLP sensor may cause harsh engagements and firm shift feel. Improper shifting or shift selection and no engine cranking may also result.

Profile Ignition Pickup (PIP)

The PIP located in distributor, sends engine RPM and crankshaft position to PCM. Signal received by the PCM affects torque converter clutch operation.

Programmable Speedometer/Odometer Module (PSOM)

The PSOM receives input from rear brake anti-lock sensor, which is mounted on rear axle differential housing. Vehicle speed (mph) signal is output to PCM. PSOM failure may cause harsh engagements, firm shift feel and abnormal shift schedule. Unexpected downshifts may occur at closed throttle and abnormal TCC operation or engages at WOT. Transmission Control Indicator Light (TCIL) may flash.

Throttle Position Sensor (TPS)

The TPS is a potentiometer mounted to the engine throttle body on gasoline engines and fuel injection pump on diesel engines. The PCM receives a signal from the TPS relaying throttle plate position (gas engines) or fuel delivery (diesel engines). TPS failure will cause PCM to operate in fail safe mode and raise line pressure to prevent transmission damage. This condition will result in harsh engagements, firm shift feel, abnormal shift schedule and TCC not engaging or cycling.

Transmission Control Switch (TCS)

Switch is mounted on shift lever handle. On/Off operation is displayed by Transmission Control Indicator Light (TCIL). Switch controls operation of 4th gear. Malfunction of switch will cause lack of 4th gear disable function.

Transmission Oil Temperature (TOT) Sensor

The TOT sensor is located on the solenoid body assembly. The PCM monitors voltage across the TOT thermistor to determine transmission temperature. Depending on temperature, the PCM controls line pressure, shift scheduling and TCC operation. Malfunction of sensor will cause incorrect line pressure and possible lack of TCC operation.

Vehicle Speed Sensor (VSS)

The VSS is a magnetic pickup that sends vehicle speed signal to the PCM. Malfunction of sensor may cause harsh engagements of shifts. Lack of 4th gear, TCC lock-up, or engine braking in 2nd or 3rd gear may also be present.

Electronic Pressure Control (EPC) Solenoid

The EPC receives signal from the PCM to control line pressure and backout valve function. If EPC fails in ON position, transmission is operated in failsafe mode. Line pressure is approximately 120 psi. Harsh engagements and shifts will result. If EPC fails in OFF position, line pressure is approximately 90 psi. Harsh engagements and shifts will result.

KOEO & KOER Codes (Hard Faults)

These codes indicate faults are present at time of testing. A hard fault may cause CHECK ENGINE light or Malfunction Indicator Light (MIL) to glow and remain on until fault is repaired. If KOEO or KOER codes are retrieved during KOEO SELF-TEST or KOER SELF-TEST, use SERVICE CODE REFERENCE CHARTS to find correct testing and repair procedures.

Continuous Memory Codes (Soft Faults)

These codes indicate a fault that may or may not be present at time of testing. These codes are used to diagnose intermittent problems. Continuous Memory Codes are retrieved during KOEO SELF-TEST. Some codes may turn on MIL or CHECK ENGINE light. Corresponding soft trouble code will be retained in PCM memory. If fault does not reoccur within 40 warm-up cycles (80 cycles on some models), PCM will automatically clear code. Technician may clear service codes from memory. See CLEARING CODES . Intermittent faults may be caused by a sensor, connector or wiring-related problems.

RETRIEVING CODES

Service codes are retrieved from EEC-IV system through self-test connector. Various methods and test equipment may be used to access these codes

1. Analog Volt-Ohmmeter (VOM)
2. Scan Tester
3. In-Dash Malfunction Indicator Light (MIL) or CHECK ENGINE light
4. STAR Series Tester

DATA LINK CONNECTOR (DLC) LOCATIONS

Separator Pulse

Single 1/2-second separator pulse is issued 6-9 seconds after last KOEO code. Continuous Memory Codes (soft faults) are then displayed 6-9 seconds after 1/2-second separator pulse. Some digital test equipment may display separator code as "10" instead of "1".

Pass Codes

A Code 11 or 111 indicates no service codes were recorded in that portion of test; system passes that portion of test. If Code 11 or 111 is not retrieved in KOEO SELF-TEST , codes retrieved during KOER SELF-TEST may not be valid. Code 11 or 111 (pass code) must be obtained in KOEO SELF-TEST . A Code 11-1-11 or 111-1-111 output during KOEO SELF-TEST indicates no KOEO code or Continuous Memory Code was recorded.

Continuous Memory Codes

These codes result from information stored by PCM during continuous self-test monitoring. Codes are displayed after separator pulse code in KOEO SELF-TEST . Use these codes for diagnosis only when KOEO SELF-TEST and KOER SELF-TEST result in Code 11 or 111 (pass code) and all steps under QUICK TEST are successfully completed. A few codes are exceptions which may be checked after KOEO codes have been repaired. These codes indicate faults recorded within last 40 engine starts (80 engine starts on some models). Fault may or may not be currently present. See SERVICE CODE REFERENCE CHARTS .

Fast Codes

At start of KOEO SELF-TEST and after Wide Open Throttle (WOT) request in KOER SELF-TEST . PCM outputs short bursts of information, known as FAST CODES, which were used by manufacturer during assembly. With most equipment, these code bursts are not visible; an entire code sequence lasts less than 1/2 second. If this fluctuation is visible on test equipment, ignore it.

Scheme 83

CLEARING CODES

To clear codes from PCM memory, start KOEO SELF-TEST under QUICK TEST . When service codes appear on test equipment or CHECK ENGINE light, disconnect jumper wire from Self-Test Input (STI) connector. If using STAR Series Tester, unlatch center button. This procedure erases Continuous Memory Codes from PCM memory. If problem has not been corrected or fault is still present, hard code will immediately be reset in PCM memory.

VISUAL CHECK

Complete a basic inspection of engine compartment and all components before proceeding to self-diagnostic tests. Ensure vacuum hoses and EEC-IV wiring harnesses are properly connected.

EQUIPMENT HOOKUP

Apply parking brake, and place shift lever in "P" position. Block drive wheels. Turn off all electrical loads. Connect appropriate test equipment to vehicle as follows: Analog Volt-Ohmmeter (VOM)

1. Turn ignition switch to OFF position. Set VOM at 0-15V DC range. Connect positive lead of VOM to positive battery terminal.
2. Connect negative VOM lead to Self-Test Output (STO) terminal of self-test connector. (Scheme 84) Connect timing light, and go to «KOEO SELF-TEST»(ref-55669-S17454036442001100800000). Activate KOEO SELF-TEST by connecting jumper wire from Self-Test Input (STI) pigtail to signal return terminal of self-test connector with ignition on.

Scan Tester

Follow manufacturer instructions to hook up equipment and record service codes.

STAR Series Tester

Turn ignition switch to OFF position. Connect color-coded adapter cable leads to diagnostic tester. Connect 2 service connectors of adapter cable to vehicle self-test connector and STI pigtail connector. Connect timing light. Go to KOEO SELF-TEST .

CHECK ENGINE Light/Malfunction Indicator Light (MIL)

Turn ignition on. Connect a jumper wire between Self-Test Input (STI) pigtail and signal return (SIG RTN) terminal of Data Link Connector (DLC). (Scheme 84) Go to KOEO SELF-TEST.

Scheme 84

ADDITIONAL SYSTEM FUNCTIONS

Additional diagnostic system features are available to help diagnose driveability problems and service EEC-IV systems.

CHECK ENGINE LIGHT & MALFUNCTION INDICATOR LIGHT (MIL)

CHECK DCL light, CHECK ENGINE light and MIL are intended to alert driver of certain malfunctions in EEC-IV system.

Light may also be used to retrieve service codes stored in PCM. When hooked up for KOEO SELF-TEST or KOER SELF-TEST, light will display all codes which turn on light during vehicle operation, not just Continuous Memory Codes.

If light comes on during vehicle operation, vehicle should be inspected as soon as possible. Immediately turning off engine is not necessary; vehicle can be driven with light on.

If light comes on and then goes off during vehicle operation, code causing light to glow will be stored in PCM memory as a Continuous Memory Code.

Light should come on when ignition is turned on and go out when engine is started. If hard fault codes are not present, PCM turns out light when it receives a Profile Ignition Pick-Up (PIP) signal. If light does not come on, see SYMPTOMS in the TESTS W/O CODES article in ENGINE PERFORMANCE.

1. For 1993 Model Vehicles, see «TESTS W/O CODES»(ref-22823)
2. For 1994 Bronco, see «TESTS W/O CODES»(ref-22970)
3. For 1994 F Series Pickup, see «TESTS W/O CODES»(ref-22976)
4. For 1994 E Series, see «TESTS W/O CODES»(ref-22980)

OUTPUT STATE CHECK

Output State Check is used as an aid in servicing output actuators associated with EEC-IV system. It allows technicians to energize and de-energize most system output actuators on command. This mode is entered from KOEO SELF-TEST after all codes have been retrieved. Leave SELF-TEST activated, and depress throttle to initiate test sequence. Each time throttle is depressed and released, output actuators will change state (from on to off or off to on).

Failure Mode Effects Management (FMEM), Code 98 Or 998 -FMEM mode allows system operation when sensors fail or transmit signals that are out of normal operating range. During FMEM mode, PCM substitutes a mid-range signal for defective sensor while continuing to monitor sensor. If faulty sensor's signals return to normal operating range, PCM will use those signals. A Code 98 or 998 will be displayed when FMEM mode is in effect.

SUMMARY

If no service codes (or pass code 11-1-11 or 111-1-111) is present but driveability problem still exists, return to TROUBLE SHOOTING in AUTO TRANS OVERHAUL - E4OD article.

SERVICE CODE REFERENCE CHARTS

Note. In addition to transmission fault codes, engine-related fault codes may be output during QUICK TEST procedure. These fault codes pertain to engine performance and must be repaired first as engine performance will greatly affect transmission operation. For information and testing procedures of engine-related fault codes and components, see See the appropriate TESTS W/ CODES article in ENGINE PERFORMANCE.

CODE REFERENCE CHART

HOW TO USE CIRCUIT/PINPOINT TESTS

1. Ensure all non-EEC related faults found while performing TROUBLE SHOOTING steps in the «AUTO TRANS OVERHAUL - E4OD»(ref-25360) article have been corrected. DO NOT perform any CIRCUIT/PINPOINT TEST unless specifically instructed by a «QUICK TEST»(ref-55669-S15424754732001100800000) procedure. Follow each test step in order until fault is found. DO NOT replace any part unless directed to do so. When more than one code is retrieved, start with first code displayed.
2. CIRCUIT/PINPOINT TESTS ensure electrical circuits are okay before sensors or other components are replaced. Always test circuits for continuity between sensor and PCM. Test all circuits for short to power, opens or short to ground. Voltage Reference (VREF) and Voltage Power (VPWR) circuits should be tested with KOEO or as specified in CIRCUIT/PINPOINT TESTS.
3. DO NOT measure voltage or resistance at PCM. DO NOT connect any test light unless specified in testing procedure. All measurements are made by probing rear of connector. Isolate both ends of a circuit and turn ignition off when checking for shorts or continuity, unless instructed otherwise.
4. Disconnect solenoids and switches from harness before measuring continuity and resistance or applying voltage. After each repair, check all component connections and repeat «QUICK TEST»(ref-55669-S15424754732001100800000) .
5. An open circuit is defined as a resistance reading of greater than 5 ohms. This specification tolerance may be too high for some items in EEC-IV system. If resistance approaches 5 ohms, always clean suspect connector and coat it with protective dielectric silicone grease. A short is defined as a resistance reading of less than 10 k/ohms to ground, unless stated otherwise in CIRCUIT/PINPOINT TEST.

CIRCUIT & PINPOINT TESTS

Note. PINPOINT TESTS are diagnostic formats used to test and service EEC-IV system. PINPOINT TESTS check transaxle circuits, sensors and actuators.

Note. CIRCUIT TESTS are diagnostic formats used to test and service EEC-IV system. CIRCUIT TESTS check engine circuits, sensors and actuators.

Scheme 85

Scheme 86

1. E4OD Electronic Diagnostics Ensure transmission harness connector is in acceptable condition. Repair as necessary. Perform KOEO test until Continuous Memory trouble code(s) have been displayed. See «QUICK TEST»(ref-55669-S15424754732001100800000). Depress throttle to WOT and release. If vehicle enters Output State, go to next step. If vehicle will not enter Output State, see the appropriate TESTS W/ CODES article in ENGINE PERFORMANCE.
2. Check Electrical Signal Operation Disconnect transmission harness connector. Inspect condition of connector and repair as needed. Using DVOM (20-volt scale), connect positive lead to transmission harness connector VPWR terminal. (Scheme 86) Connect negative lead to suspect solenoid circuit. Depress and release throttle to cycle solenoid output. If voltage changes at least.5 volt, go to step 5). If voltage is unaffected, go to next step. (Scheme 86): Identifying Transmission Harness Connector TRANSMISSION HARNESS CONNECTOR TERMINAL IDENTIFICATION Terminal Number Circuit Description (1) BOB Test Pin Number 1 VPWR 37/57 2 SS2 (2) 19 3 SS1 (3) 52 4 TCC Solenoid 53 5 CCS 55 6 Not Used --- 7 TOT (4), (5) 42 8 Sensor SRTN 46 9 Not Used --- 10 Not Used --- 11 EPC 38 12 EPC Power (6) 37/57 (1) Breakout Box. (2) Test pin No. 52, 5.0L models. (3) Test pin No. 51, 5.0L models. (4) Test pin No. 7, Diesel models. (5) Test pin No. 49, 5.0L models. (6) Test pin No. 35, Diesel models.
3. Check Continuity Of Solenoid Signal & VPWR Harnes Circuits Ensure ignition is off. Disconnect PCM 60-pin connector, and inspect it for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure and record resistance between Breakout Box test pin No. 19 or 52 and corresponding transmission harness connector terminal on all models except 5.0L. On 5.0L models, measure and record resistance between Breakout Box test pin No. 51 or 52 and corresponding transmission harness connector terminal. (Scheme 86) Measure and record resistance. Measure and record resistance between test pins No. 37 and 57 and transmission harness connector VPWR terminal. If any resistance is greater than 5 ohms, repair open circuit. Connect all components. Disconnect Breakout Box and repeat Quick Test. If resistance is 5 ohms or less, go to next step.
4. Check Solenoid Harness For Shorts To Power & Ground Measure and record resistance between Breakout Box test pins No. 19 or 52 and test pins No. 37 and 57 on all models except 5.0L. On 5.0L models, measure and record resistance between Breakout Box test pins No. 51 or 52 and test pins No. 37 and 57. Measure and record resistance between test pins No. 40, 46 and 60, and ground. If any resistance is less than 10 k/ohms, repair short circuit. Connect all components. Disconnect Breakout Box and repeat Quick Test. If resistance is 10 k/ohms or more, go to next step.
5. Solenoid Functional Test Connect Transmission Tester (007-0085A). Perform solenoid voltage test. See tester instructions. If solenoid activates (LED Green), go to next step. If solenoid does not activate, go to step 6). Check if diode test light is illuminated. If diode is okay, go to next step. If diode test light is not illuminated, replace solenoid body assembly. Erase all trouble codes and road test vehicle. Repeat QUICK TEST.
6. Transmission Drive Test Perform tester drive test. See tester instructions. If vehicle upshifts when operated with tester, erase all trouble codes. See «CLEARING CODES»(ref-55669-S02254125382001100800000). Perform TRANSMISSION DRIVE CYCLE TEST. Repeat «QUICK TEST»(ref-55669-S15424754732001100800000). If vehicle does not upshift when operated by tester, go to next step.
7. Check Resistance of Solenoid Set tester Bench/Drive switch to Bench mode. Set Gear Selector switch to OHMS/DIODE CHECK. Connect ohmmeter negative lead to SS1 jack and positive lead to VPWR jack on tester. Measure and record resistance. Connect ohmmeter negative lead to SS2 jack and positive lead to VPWR jack on tester. Resistance for both solenoids should be 20-30 ohms. If resistance is within specification, go to next step. If resistance is not within specification, replace solenoid body assembly. Erase all codes. See «CLEARING CODES»(ref-55669-S02254125382001100800000). Repeat QUICK TEST.
8. Check Solenoid For Short To Ground Check continuity between BAT(-) terminal and between SS1 and SS2. Check continuity between BAT(-) terminal and each VPWR terminal. If continuity exists for any circuit, replace solenoid body assembly. Erase all codes. See «CLEARING CODES»(ref-55669-S02254125382001100800000). Repeat QUICK TEST. If continuity does not exist, see TROUBLE SHOOTING in «AUTO TRANS OVERHAUL - E4OD»(ref-25360) article.

WIDE OPEN THROTTLE A/C CUT-OUT (WAC) & A/C DEMAND SWITCH

Diagnostic Aids: Perform this test when instructed by QUICK TEST . To prevent replacing good components, check the following non-EEC components and systems

1. Refrigerant charge.
2. Low ambient temperature (less than 45°F).

This test is only intended to diagnose

1. Wiring harness circuits (WAC, VPWR, GND, POWER-TO-CLUTCH and ACD).
2. WAC relay.
3. Faulty PCM.

WOT A/C Cut-Out Circuit (Bronco, "F" Series & "E" Series). Scheme 87

TEST PIN NO. 10 (ACCS) WIRE COLOR IDENTIFICATION

Diagnostic Aids: Before entering this test, ensure A/C selector is in OFF position and shift selector is in PARK (A/T). If A/C was on, repeat QUICK TEST . If Code 539 is present, continue with this test.

Note. Procedure begins at step 40). No test procedures have been omitted.

1. 40) Code 539: Check A/C Input Code 539 indicates ACCS input to PCM was high during SELF-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. Turn ignition on. Measure voltage between test pin No. 10 at breakout box and chassis ground. If voltage is more 1.0 volt, verify A/C switch operation, repair as necessary. If A/C switch is okay, repair short to power in A/C circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-55669-S15424754732001100800000) . If voltage is 1.0 volt or less on all models except 7.3L diesel, replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-55669-S15424754732001100800000) . If voltage is 1.0 volt or less on 7.3L diesel, go to next step.
2. 41) Check For Short To Power In PCM Ensure ignition is off. With Breakout Box still installed, connect PCM to Breakout Box. Disconnect A/C clutch electrical harness. With KOEO, measure voltage between breakout box test pin No. 10 and No. 40. If voltage is more than 5 volts, replace PCM. Connect all components and repeat «QUICK TEST»(ref-55669-S15424754732001100800000) . If voltage is 5 volts or less, connect all components. Go to «CIRCUIT TEST TD»(ref-55669-S37422126202001100800000) .

TRANSMISSION CONTROL SWITCH (TCS), TRANSMISSION CONTROL

SWITCH, MODULE (TCSM) & TRANSMISSION CONTROL INDICATOR LIGHT (TCIL)

Diagnostic Aids

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

1. Powertrain Control Module (PCM).
2. Wiring harness circuits (4x4 Low, TCIL and TCS).

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).

4x4 Low & Overdrive Cancel Circuits (Touch Drive Option). Scheme 88

4x4 Low & Overdrive Cancel Circuits (W/O Touch Drive Option). Scheme 89

1. Code 47/633 & 691 Code 47/633 indicates 4x4 low selector lever is not in 4x2 or 4x4 high position (KOEO). Code 691 is set when a stored KAM value for engine RPM or vehicle speed is compared to a calculated engine RPM/vehicle speed and do not match. Possible malfunction causes Damaged 4x4 low switch or 4x4 selector lever position. Shorted harness. Damaged PCM. Internal damage to transfer case. : If 4x4 lever is in 4x2 or 4x4 high position, go to next step. If 4x4 lever is not in 4x2 or 4x4 high position, repeat «QUICK TEST»(ref-55669-S15424754732001100800000) with shift lever in correct position.
2. Code 65/632 Or 653 Code 65/632 or 653 indicates that the TCS was not cycled between engine ID Code and WOT check during «KOER SELF-TEST»(ref-55669-S18343792902001100800000) . 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 cycled during «KOER SELF-TEST»(ref-55669-S18343792902001100800000) , go to step 4). If TCS did not cycle during «KOER SELF-TEST»(ref-55669-S18343792902001100800000) , repeat KOER SELF-TEST while cycling TCS.
3. Code 97/623 or 631 Code 97/623 or 631 indicates transmission control indicator light circuit fault during «KOEO SELF-TEST»(ref-55669-S17454036442001100800000) . Possible causes for this fault are: Burned out bulb. Open or shorted wiring harness. If TCS cycled during «KOEO SELF-TEST»(ref-55669-S17454036442001100800000) , go to step 5). If TCS did not cycle during «KOEO SELF-TEST»(ref-55669-S17454036442001100800000) , repeat KOER SELF-TEST while cycling TCS.
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. For TCS circuit, measure voltage between test pin No. 41 and test pin No 40 or 60 while cycling TCS several times. For 4x4 low circuit, measure voltage between test pin No. 12 and test pin No 40 or 60 while moving lever between 4x2 and 4x4 low several times. If voltage cycles replace PCM. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-55669-S15424754732001100800000) . If voltage does not cycle, go to next step if diagnosing a trouble code or step 7) if diagnosing a driveability symptom.
5. Check Circuits For Short To Ground Turn ignition off. Leave PCM disconnected from breakout box. To test 4x4 low circuit, disconnect 4x4 low switch connector. Inspect connector for damage and repair as necessary. Measure and record resistance between test pin No. 12 and test pin 40 or 60. To test TCS circuit, 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 k/ohms, go to next step if Code 97/631 was originally present, or step 8) if Codes 47/633, 65/632 or 691 were originally present. If any reading is 10 k/ohms or less, repair short circuit. Repeat «QUICK TEST»(ref-55669-S15424754732001100800000) . If code is still present, go to step 7).
6. Check Power Through TCIL Circuit Turn ignition off. Leave PCM disconnected from breakout box. Measure voltage between test pin No. 32 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-55669-S15424754732001100800000) . If voltage is 10.5 volts or less, go to next step.
7. Check Output Driver Voltage Signal Leave PCM disconnected from breakout box. Turn ignition on. Measure voltage between test pin No. 32 (TCS circuit) or test pin No. 12 (4x4 low circuit) 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-55669-S15424754732001100800000) .
8. Check 4x4 Low Or TCS Circuit Continuity Turn ignition off. Leave PCM disconnected from breakout box. Ensure TCS is disconnected. To test 4x4 low circuit, check continuity between breakout box test pin No. 12 and 4x4 low switch touch drive module harness connector. To test TCS circuit, measure resistance between KEY POWER terminal of fuse (No. 5 on "E" series or No.17 on Bronco/"F" series) at instrument panel fuse block and TCS wiring harness connector. Also, measure resistance between test pin No. 41 at breakout box and signal wire 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-55669-S15424754732001100800000) . If each reading is less than 5 ohms, go to next step.
9. Check For Short To Power Turn ignition off. Leave PCM disconnected from breakout box. To test TCS system, ensure TCS is disconnected. Measure resistance between test pin No. 41 and test pin 37 or 57. Also, measure resistance between test pin No. 32 and test pin No. 37 or 57. To test 4x4 low system, ensure 4x4 low switch is disconnected. Measure resistance between test pin No. 12 and test pins No. 37/57. If each reading is more than 10 k/ohms, replace appropriate switch. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-55669-S15424754732001100800000) . If any reading is 10 k/ohms or less, repair short circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-55669-S15424754732001100800000) .