SELF-DIAGNOSTIC SYSTEM
| CAUTION | When battery is disconnected, vehicle computer and memory systems may lose memory data. Drive Ability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION section before disconnecting battery. |
DIAGNOSTIC FORMATS
QUICK TEST and CIRCUIT TESTS are diagnostic formats used to test and service Electronic Engine Control (EEC) system. QUICK TEST allows technician to identify problems and retrieve trouble codes. CIRCUIT TESTS check circuits, sensors and actuators. Before starting any CIRCUIT TEST, follow all steps under QUICK TEST to find correct CIRCUIT TEST. If vehicle passes QUICK TEST and no driveability symptoms or intermittent faults exist, EEC system is okay.
TROUBLE CODES
During QUICK TEST, diagnostic trouble codes are retrieved from PCM memory. See QUICK TEST for self-test procedures. These codes indicate faults are present at time of testing. A hard fault may cause Malfunction Indicator Light (MIL) to go on and remain on until fault is repaired. Codes may be cleared from PCM memory after they have been recorded or repaired. See CLEARING CODES.
KOEO SELF-TEST
Ensure engine is warmed to normal operating temperature. If engine does not start (or stalls after starting), continue KOEO SELF-TEST. Turn ignition off. Wait 10 seconds. Ensure test equipment is properly attached. Turn ignition on (engine off). Record all KOEO Codes.
If a Code 55 (pass code) is retrieved, testing is complete. If a Code 55 is not retrieved, service KOEO codes. See TROUBLE CODE REFERENCE under CIRCUIT TESTS. If PCM will not output codes, go to CIRCUIT TEST VPWR. If trouble codes are retrieved, service trouble codes in order retrieved.
TROUBLE CODE REFERENCE
| Trouble Code | Circuit Test |
|---|---|
| 11 | CMP |
| 12 | MAF |
| 13 | ECT |
| 14 | VSS |
| 21 | IGNS |
| 31 | (1) |
| 32 | EGRC |
| 33 | HO2S |
| 34 | KS |
| 35 | EGRT |
| 43 | TP |
| 45 | INJL |
| 51 | INJS |
| 55 | (2) |
| (1) Replace PCM. (2) EEC System Pass Code. | |
| (1) | Replace PCM. |
| (2) | EEC System Pass Code. |
TROUBLE CODE REFERENCE
Note. In following tests, circuit diagrams and illustrations are courtesy of Ford Motor Co.
CIRCUIT TEST CMP - CAMSHAFT POSITION (CMP) SENSOR
1) Check Power To CMP Turn ignition off. Disconnect CMP sensor wiring harness connector. Turn ignition on. Measure voltage between CMP sensor wiring harness connector VPWR terminal and ground. If voltage is less than 10 volts, go to step 4). If voltage is 10 volts or more, go to next step.
2) Check Ground At CMP Turn ignition off. Leave CMP sensor disconnected. Measure resistance between CMP sensor wiring harness connector GND terminal and ground. If resistance is 5 ohms or more, repair GND circuit. If resistance is less than 5 ohms, go to next step.
3) Check CMP Sensor Turn ignition off. Remove distributor from engine, leaving CMP sensor connected. Turn ignition on. While slowly rotating distributor, measure voltage between CMPREF terminal at sensor connector and ground. Also measure voltage between CMP terminal at sensor connector and ground. If voltage does not fluctuate 0.0-5.0 volts, replace distributor and CMP sensor. If voltage fluctuates 0.0-5.0 volts, check CMP signal plate for damage and dust. If plate is okay, go to step 5).
4) Check Continuity Between CMP & Engine Continuity Relay Turn ignition off. Disconnect CMP sensor. Disconnect engine continuity relay wiring harness connector, located in left engine compartment fuse panel. Check for continuity between VPWR terminal of relay connector and VPWR terminal of CMP sensor connector. (Scheme 1) If continuity is not present, repair VPWR circuit. If continuity is present, go to CIRCUIT TEST VPWR.
5) Check Continuity Between CMP & PCM Turn ignition off. Leave CMP disconnected. Install Breakout Box (007-00033), leaving PCM disconnected. Check for continuity between breakout box test pin No. 56 and CMP terminal of CMP wiring harness connector. Also check for continuity between breakout box test pin No. 43 and CMPREF terminal of CMP harness connector. If continuity is not present, repair circuit as necessary. If continuity is present, replace PCM.
CMP & Engine Continuity Relay Connector Terminal ID. Scheme 1
Diagnostic Aids
Perform this test when directed by CIRCUIT TEST VPWR. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuits (DC, DLC and GND).
Identifying DLC Circuits & Connector Terminals. Scheme 2
Identifying DC Circuits & Connector Terminals. Scheme 3
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| DLC | 7 | 45 | Yellow/Red |
| DLC | 14 | 51 | Yellow/Blue |
| DLC | 15 | 32 | Yellow/Black |
| GND | 48 | 20 | (2) Black/Red |
| (1) Rotunda Breakout Box (007-00033). (2) Black at DLC connector. | |||
| (1) | Rotunda Breakout Box (007-00033). |
| (2) | Black at DLC connector. |
DLC CIRCUIT INFORMATION
1) Check Ground At DLC Turn ignition off. Locate Data Link Connector (DLC). Measure resistance between GND terminal at DLC and ground. If resistance is less than 5 ohms, go to next step. If resistance is at least 5 ohms, repair ground circuit.
2) Check For Continuity Turn ignition off. Install Breakout Box(007-00033), leaving PCM disconnected. Check for continuity between breakout box and DLC connector as follows
- Test pin No. 32 of breakout box and DLC (Yellow/Black wire) terminal of DLC harness connector.
- Test pin No. 45 of breakout box and DLC (Yellow/Red wire) terminal of DLC harness connector.
- Test pin No. 51 of breakout box and DLC (Yellow/Blue wire) terminal of DLC harness connector.
If continuity is not present, go to next step. If continuity is present, go to CIRCUIT TEST PGC.
3) Check Power At DC Turn ignition off. Disconnect MIL Diagnostic Connector (DC), located in left side of engine compartment, below coolant overflow reservoir. Turn ignition on. Measure voltage between DC harness connector Gray/Blue wire and ground. If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, check 10-amp METER fuse of interior fuse box. If fuse is okay, repair Gray/Blue wire.
4) Check Continuity Turn ignition off. Leave PCM disconnected from breakout box. Check for continuity between breakout box test pin No. 48 and DC terminal of DC harness connector. If continuity is not present, repair circuit as necessary. If continuity is present, go to CIRCUIT TEST PGC.
Perform this test when directed by QUICK TEST. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuits (ECT and SIGRTN).
Identifying ECT Circuits & Connector Terminals. Scheme 4
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| ECT | 18 | 7 | Light Green/Red |
| SIGRTN | 21 & 29 | 46 | White/Black |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
ECT CIRCUIT INFORMATION
1) Check PCM Input Signal A scan tester with ECT output signal reading capability is required for step 1). If scan tester is not available, go to next step. Turn ignition off. Connect scan tester to DLC. Start engine. Observe signal as engine warms to operating temperature. If ECT output signal value gradually increases to 158°F (70°C), system is operating correctly. If ECT related driveability problems are still present, replace PCM. If ECT output signal value does not gradually increase to 158°F (70°C), go to next step.
2) Check ECT Voltage Turn ignition off. Disconnect ECT sensor wiring harness connector. Turn ignition on. Measure voltage between sensor wiring harness connector ECT terminal and ground. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 4).
3) Check ECT Sensor Resistance Allow engine to cool. Start engine. Use a thermometer to monitor engine coolant temperature. Warm engine to temperature specifications shown in ECT SENSOR RESISTANCE SPECIFICATIONS table. Turn ignition off. Disconnect ECT sensor wiring harness connector. Measure resistance between connector terminals. If resistance is correct, replace PCM. If resistance is not correct, replace ECT sensor.
| Temperature °F (°C) | Ohms |
|---|---|
| 68 (20) | 2100-2900 |
| 122 (50) | 680-1000 |
| 176 (80) | 300-330 |
ECT SENSOR RESISTANCE SPECIFICATIONS
4) Check SIGRTN Circuit Turn ignition off. Install Breakout Box(007-00033), leaving PCM disconnected. Disconnect ECT sensor wiring harness connector. Measure resistance between breakout box test pin No. 46 and SIGRTN terminal of ECT sensor wiring harness connector. If resistance is 5 ohms or less, repair SIGRTN circuit between ECT sensor and PCM. If resistance is more than 5 ohms, repair ECT circuit between ECT sensor and PCM.
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuits (EGRC and PWR).
EGRC Circuits & Connector Terminal ID. Scheme 5
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| EGRC | 102 | 33 | Gray |
| PWR | N/a | N/a | White/Red |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
EGRC CIRCUIT INFORMATION
1) Check PCM Output Signal Turn ignition off. Connect scan tester to DLC. Using scan tester, cycle solenoid on and off. If solenoid cycles, go to step 5). If solenoid does not cycle, go to next step.
2) Check Power To EGRC Solenoid Turn ignition off. Disconnect EGRC solenoid wiring harness connector. Turn ignition on. Measure voltage between harness connector PWR terminal and ground. If voltage is less than 10 volts, repair PWR circuit to EGRC solenoid. If voltage is at least 10 volts, go to next step.
3) Check EGRC Solenoid Turn ignition off. Check vacuum hoses for damage or loose fit. Repair as necessary. With connector removed, apply 12 volts to EGRC solenoid PWR terminal. Connect solenoid EGRC terminal to ground. Apply light air pressure to port "A" and verify pressure is released through port "B". (Scheme 6) If airflow is correct, go to next step. If airflow is not correct, replace solenoid.
4) Check EGRC Circuit Turn ignition off. Install Breakout Box(007-00033), leaving PCM disconnected. Leave EGRC wiring harness connector disconnected. Measure resistance between breakout box test pin No. 33 and EGRC terminal of EGRC solenoid harness connector. Resistance should be 5 ohms or less. Check for continuity between breakout box test pin No. 33 and ground. Resistance should be 10,000 ohms or more. If resistance is as specified, replace PCM. If resistance is not as specified, repair circuit between PCM and EGRC solenoid.
5) Check EGR Valve Disconnect vacuum hose from EGR valve. Using pump, apply vacuum to EGR valve. If EGR valve diaphragm lifts, go to CIRCUIT TEST EGRT. If EGR valve diaphragm does not lift, replace EGR valve.
Identifying EGRC Solenoid Terminals & Ports. Scheme 6
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuits (EGRT and SIGRTN).
EGRT Circuits & Connector Terminal ID. Scheme 7
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| EGRT | 8 | 25 | White/Pink |
| SIGRTN | 21 & 29 | 46 | White/Black |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
EGRT CIRCUIT INFORMATION
1) Check EGRT Signal To PCM Turn ignition off. Connect scan tester to DLC. Using scan tester, check EGRT sensor voltage. If voltage is less than 4.5 volts, EGRT sensor is okay and testing is complete. If voltage is 4.5 volts or more, go to next step.
2) Check EGRT Sensor Resistance Allow engine to cool. Start engine. Use a thermometer to monitor engine coolant temperature. Warm engine to temperature specifications shown in EGRT SENSOR RESISTANCE SPECIFICATIONS table. Turn ignition off. Disconnect EGRT wiring harness connector. Measure resistance between connector terminals. If resistance is correct, go to next step. If resistance is not correct, replace EGRT sensor.
| Coolant Temperature °F (°C) | M Ohms |
|---|---|
| 68-120 (20-49) | 2.25-2.55 |
| 130-148 (55-65) | 1.75-2.25 |
| 150-165 (66-74) | 1.40-1.75 |
| 168-190 (76-88) | 1.00-1.40 |
EGRT SENSOR RESISTANCE SPECIFICATIONS
3) Check EGRT Sensor Start engine and allow to idle until engine is at normal operating temperature. Raise engine speed to 2000 RPM. Check voltage at EGRT sensor wiring harness connector terminals. Apply vacuum to EGR valve. If voltage drops from more than one volt to less than one volt, go to next step. If voltage does not drop as specified, replace EGRT sensor.
4) Check EGRT Circuit Turn ignition off. Install Breakout Box(007-00033), leaving PCM disconnected. Leave EGRT wiring harness connector disconnected. Disconnect in-line connector located on right side of intake plenum. Measure resistance between breakout box test pin No. 25 and EGRT terminal of EGRT in-line connector. Measure resistance between EGRT terminal of EGRT in-line connector and EGRT terminal of EGRT sensor harness connector. Resistance should be 5 ohms or less. Reconnect in-line connector. Measure resistance between breakout box test pin No. 25 and ground. Resistance should be 10,000 ohms or more. If resistance is as specified, go to next step. If resistance is not as specified, repair or replace circuit.
5) Check SIGRTN Circuit Leave ignition off and EGRT wiring harness connector disconnected. Measure resistance between breakout box test pin No. 46 and SIGRTN terminal of in-line connector. Measure resistance between SIGRTN terminal of in-line connector and SIGRTN terminal of EGRT wiring harness connector. If both resistance values are 5 ohms or less, replace PCM. If either resistance value exceeds 5 ohms, repair circuit as necessary.
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuits (HO2S and PWR).
Identifying HO2S Circuit & Connector Terminals. Scheme 8
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| HO2S | 19 | 29 | Green/Black |
| PWR | N/a | N/a | Blue/Yellow |
| HEATER | 106 | 52 | Black |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
HO2S CIRCUIT INFORMATION
1) Check Power To HO2S Turn ignition off. Disconnect HO2S wiring harness connector. Turn ignition on. Measure voltage between HO2S harness connector PWR terminal and ground. If voltage is less than 10 volts, repair PWR circuit. If voltage is 10 volts or more, go to next step.
2) Check HO2S Ground Turn ignition off. Install Breakout Box (007-00033), leaving PCM disconnected. Leave HO2S wiring harness connector disconnected. Measure resistance between breakout box test pin No. 52 and HEATER terminal of HO2S harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair or replace circuit as necessary.
3) Check HO2S Circuit Turn ignition off. Leave HO2S wiring harness connector disconnected. Measure resistance between breakout box test pin No. 29 and HO2S terminal of HO2S harness connector. Resistance should be 5 ohms or less. Measure resistance between breakout box test pin No. 29 and ground. Resistance should be 10,000 ohms or more. If resistance is as specified, replace HO2S. If resistance is not as specified, repair or replace circuit as necessary.
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuit (IGNS, IGNC, GND and PWR).
Identifying IGNS Circuit & Connector Terminals. Scheme 9
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| IGNS | 1 | 36 | Blue |
| IGNC | 3 | 4 | Red |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
IGNS CIRCUIT INFORMATION
1) Check Power To Resistor/Condenser Turn ignition off. Disconnect resistor/condenser harness connector. Turn ignition on. Measure voltage between PWR (White/Red wire) terminal of resistor/condenser wiring harness connector and ground. If voltage is less than 10 volts, repair PWR circuit. If voltage is 10 volts or more, go to next step.
2) Check Power To Ignition Coil Turn ignition off. Disconnect ignition coil wiring harness connector. Turn ignition on. Measure voltage between PWR terminal of ignition coil harness connector and ground. If voltage is less than 10 volts, repair PWR circuit. If voltage is 10 volts or more, go to next step.
3) Check PCM Input Signal Turn ignition off. Install Breakout Box (007-00033). Connect PCM to breakout box. Try to start engine and run at idle. Measure voltage between breakout box test pin No. 4 and ground. If vehicle starts and voltage is less than 10 volts, go to step 7). If vehicle does not start and voltage is less than 10 volts, go to step 5). If voltage is 10 volts or more, go to next step.
4) Check PCM Output Signal Turn ignition off. Leave PCM connected to breakout box. Measure voltage between test pin No. 36 and ground. With engine idling, voltage should be 0.4-0.6 volt. With engine speed at 2000 RPM, voltage should be 1.1-1.3 volts. If voltage is not as specified, replace PCM. If voltage is as specified, ignition signal is okay. Repeat QUICK TEST. If Code 21 is still present, replace PCM.
5) Check Power Transistor Turn ignition off. Disconnect power transistor wiring harness connector. Measure resistance between terminals "A" and "B". (Scheme 10) Reverse ohmmeter test leads and measure resistance again. Both measurements should be more than 1,000,000 ohms. Measure resistance between terminals "A" and "C". Reverse ohmmeter test leads and measure resistance again. Both measurements should be more than 1,000,000 ohms. If resistance is not as specified, replace power transistor. If resistance is as specified, go to next step.
Power Transistor Connector Terminal ID. Scheme 10
6) Check IGNS Circuit Turn ignition off. Leave power transistor wiring harness connector disconnected. Install Breakout Box(007-00033), leaving PCM disconnected. Measure resistance between breakout box test pin No. 36 and IGNS terminal of power transistor harness connector. Resistance should be 5 ohms or less. Measure resistance between breakout box test pin No. 36 and ground. Resistance should be 10,000 ohms or more. If resistance is as specified, test ignition coil and service as necessary. If resistance is not as specified, repair IGNS circuit.
7) Check Resistor Turn ignition off. Disconnect resistor/condenser wiring harness connector. Measure resistance between terminals "R" and "GN" of wiring harness connector. (Scheme 11) Resistance should be about 2200 ohms. If resistance is not as specified, replace resistor/condenser. If resistance is as specified, go to next step.
8) Check IGNC Circuit Turn ignition off. Leave resistor/condenser harness connector disconnected. Install Breakout Box (007-00033), leaving PCM disconnected. Measure resistance between breakout box test pin No. 4 and IGNC (Red wire) terminal of resistor/condenser harness connector. Resistance should be 5 ohms or less. Measure resistance between breakout box test pin No. 4 and ground. Resistance should be 10,000 ohms or more. If resistance is not as specified, repair IGNC circuit. If resistance is as specified, go to next step.
9) Check Ground Circuit Turn ignition off. Leave resistor/condenser harness connector disconnected. Disconnect power transistor and ignition coil wiring harness connector. Measure resistance between following connector terminals
- Green wire terminal of ignition coil and power transistor.
- Green wire terminal of ignition coil and resistor/condenser.
- Black wire terminal of power transistor and ground.
If resistance is 5 ohms or more, repair IGNC circuit. If resistance is 5 ohms or less, replace PCM.
Resistor/Condenser Connector Terminal ID. Scheme 11
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuit INJL.
Perform Road Test
Ensure engine is warmed to normal operation temperature. Start engine and allow to idle for at least 60 seconds. Drive vehicle with engine speed at 1800-3200 RPM for at least 5 seconds. Return engine to idle for at least 10 seconds. Repeat procedure 10 times or more. If MIL/CHECK ENGINE light stays on, replace PCM. If MIL/CHECK ENGINE light goes off, check for intermittent fuel injector leak. If injectors are okay, replace PCM.
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuit (KAPWR and SIG).
Identifying INJS Circuit & Connector Terminals. Scheme 12
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| INJ1 (SIG) | 101 | 58 | Green/Orange |
| INJ2 (SIG) | 110 | 59 | Green |
| INJ3 (SIG) | 103 | 12 | Green/Red |
| INJ4 (SIG) | 112 | 13 | Yellow/Purple |
| INJ5 (SIG) | 105 | 14 | Yellow/Green |
| INJ6 (SIG) | 114 | 15 | Gray/Blue |
| KAPWR | 46 | 1 | Yellow |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
INJS CIRCUIT INFORMATION
1) Check Power At Injector Connector Turn ignition off. Disconnect suspect injector wiring harness connector. Turn ignition on. Measure voltage between injector harness connector KAPWR (Yellow wire) terminal and ground. If voltage is 10-14 volts, go to next step. If voltage is not 10-14 volts, check INJ fuse (located in left engine compartment fuse panel). If fuse is okay, repair KAPWR circuit.
2) Check Injector Turn ignition off. Disconnect suspect injector wiring harness connector. Measure resistance between connector terminals. If resistance is 10-14 ohms, go to next step. If resistance is not 10-14 ohms, replace injector.
3) Check Power At PCM Turn ignition off. Install Breakout Box(007-00033), leaving PCM disconnected. Measure voltage between breakout box test pin No. 1 and ground. If voltage is 11-14 volts, go to next step. If voltage is not 11-14 volts, repair KAPWR circuit.
4) Check SIG Wire Turn ignition off. Disconnect suspect injector wiring harness connector. Measure resistance between suspect injector SIG test pin at breakout box and SIG terminal at injector harness connector. Resistance should be 5 ohms or less. Measure resistance between suspect injector SIG test pin at breakout box and ground. Resistance should be 10,000 ohms or more. If resistance is as specified, replace PCM. If resistance is not as specified, repair or replace circuit.
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuit KS.
Identifying KS Circuit & Connector Terminals. Scheme 13
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| KS | 27 | 23 | White |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
KS CIRCUIT INFORMATION
1) Check PCM Input Signal Turn ignition off. Install Breakout Box (007-00033). Connect PCM to breakout box. Start engine and allow to idle. Measure voltage between breakout box test pin No. 23 and ground. If voltage is not about 2.5 volts, go to next step. If voltage is about 2.5 volts, input signal is okay. Repeat QUICK TEST. If Code 34 is still present, replace PCM.
2) Check KS Circuit Turn ignition off. Disconnect PCM from breakout box. Disconnect KS wiring harness connector. Measure resistance between test pin No. 23 and KS terminal of knock sensor wiring harness connector. Resistance should be 5 ohms or less. Measure resistance between breakout box test pin No. 23 and ground. Resistance should be 10,000 ohms or more. If resistance is as specified, go to next step. If resistance is not as specified, repair or replace KS circuit as necessary.
3) Check KS In-Line Connector Ground Turn ignition off. Disconnect knock sensor in-line connector. Measure resistance between in-line harness connector Black/Red wire terminal and ground. If resistance is less than 5 ohms, replace knock sensor. If resistance is 5 ohms or more, repair or replace Black/Red wire circuit as necessary.
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuit (MAF+, MAF- and VPWR).
Identifying MAF Circuit & Connector Terminals. Scheme 14
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| MAF | 17 | 39 | Orange/Blue |
| MAF+ | 16 | 50 | White/Blue |
| VPWR | 38 | 37 | Red/Black |
| VPWR | 47 | 57 | Red/Black |
| VPWR | 109 | 6 | Red/Black |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
MAF CIRCUIT INFORMATION
1) Check Power To MAF Turn ignition off. Disconnect MAF wiring harness connector. Turn ignition on. Measure voltage between harness connector VPWR (Red/Black wire) terminal and ground. If voltage is less than 10 volts, go to CIRCUIT TEST VPWR. If voltage is 10 volts or more, go to next step.
2) Check MAF- Circuit Turn ignition off. Leave MAF wiring harness connector disconnected. Install Breakout Box (007-00033), leaving PCM disconnected. Measure resistance between breakout box test pin No. 39 and MAF- terminal of MAF harness connector. Resistance should be 5 ohms or less. Measure resistance between breakout box test pin No. 39 and ground. Resistance should be 10,000 ohms or more. If resistance is as specified, go to next step. If resistance is not as specified, repair or replace circuit as necessary.
3) Check MAF Sensor Turn ignition off and allow engine to cool. Disconnect MAF sensor wiring harness connector. Connect a jumper wire between VPWR terminal of harness connector and VPWR terminal at MAF sensor. Connect a jumper wire between MAF- terminal of harness connector and MAF- terminal at MAF sensor. Turn ignition on. Measure voltage between MAF+ terminal at MAF sensor and ground. Start engine and warm to operating temperature. With engine idling, repeat previous voltage measurement. Voltage should be about 0.7 volt when engine is cool (ignition on) and about 1.7 volts with engine warm and idling. If voltage is as specified, go to next step. If voltage is not as specified, replace MAF sensor.
4) Check MAF+ Circuit Turn ignition off. Leave MAF sensor and PCM wiring harness connectors disconnected. Measure resistance between breakout box test pin No. 50 and MAF+ terminal of MAF harness connector. Resistance should be 5 ohms or less. Measure resistance between breakout box test pin No. 50 and ground. Resistance should be 10,000 ohms or more. If resistance is not as specified, repair MAF+ circuit. If resistance is as specified, system is okay. Repeat QUICK TEST. If Code 12 is still present, replace PCM.
Perform this test when directed by another CIRCUIT TEST. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuit (KAPWR and GND).
Ground Circuit & Connector Terminal ID. Scheme 15
Identifying Power Circuit. Scheme 16
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| KAPWR | 46 | 1 | Yellow |
| GND | 6 & 13 | 16 | Black |
| GND | 39 | 9 | Black/Red |
| GND | 48 | 20 | Black/Red |
| GND | 107 | 40 | Black |
| GND | 108 | 60 | Black |
| GND | 116 | 49 | Black |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
PGC CIRCUIT INFORMATION
1) Check Voltage Turn ignition off. Install Breakout Box (007-00033), leaving PCM disconnected. Measure voltage between breakout box test pin No. 1 and ground. If voltage is 11-14 volts, go to next step. If voltage is not 11-14 volts, check INJ fuse (located in left engine compartment fuse panel). If fuse is okay, repair KAPWR circuit.
2) Check Ground Circuits Turn ignition off. Measure resistance between suspect ground circuit test pin at breakout box and ground. Resistance should be 5 ohms or less. If resistance is okay, replace PCM. If resistance is not okay, repair ground circuit.
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuit (TP, VREF and SIGRTN).
Identifying TP Circuit & Connector Terminals. Scheme 17
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| TP | 20 | 47 | Red |
| VREF | 37 | 26 | Brown |
| SIGRTN | 21 & 29 | 46 | White/Black |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
TP CIRCUIT INFORMATION
1) Check VREF Signal Turn ignition off. Disconnect TP sensor wiring harness connector. Turn ignition on. Measure voltage between VREF terminal of TP sensor harness connector and ground. If voltage is 4-5 volts, go to next step. If voltage is not 4-5 volts, go to CIRCUIT TEST VREF.
2) Check TP Sensor Turn ignition off. Leave TP sensor wiring harness connector disconnected. Connect ohmmeter test leads to SIGRTN and TP terminals of TP sensor. Measure resistance at following throttle positions and verify resistance is as indicated
- Throttle closed: 1000 ohms.
- Throttle at 1/2 open: 1000-10,000 ohms.
- Throttle fully opened: about 10,000 ohms.
If resistance is as specified, go to next step. If resistance is not as specified, replace TP sensor.
3) Check TP & SIGRTN Circuits Turn ignition off. Leave TP wiring harness connector disconnected. Install Breakout Box (007-00033), leaving PCM disconnected. Measure resistance between SIGRTN test pin at breakout box and SIGRTN terminal of TP sensor harness connector. Measure resistance between TP test pin at breakout box and TP terminal of TP sensor harness connector. Resistance should be 5 ohms or less. Measure resistance between breakout box test pin No. 47 and ground. Resistance should be 10,000 ohms or more. If resistance is as specified, replace PCM. If resistance is not as specified, repair circuit.
Perform this test when directed by another CIRCUIT TEST. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuit (VPWR, PWR and GND).
VPWR Circuit & Engine Cont Relay Connector Terminal ID. Scheme 18
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| GND | 4 | 44 | White/Green |
| VPWR | 38 | 37 | Red/Black |
| VPWR | 47 | 57 | Red/Black |
| VPWR | 109 | 6 | Red/Black |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
VPWR CIRCUIT INFORMATION
1) Check VPWR To PCM Turn ignition off. Install Breakout Box(007-00033), leaving PCM disconnected. Turn ignition on. Measure voltage between breakout box test pins No. 6, 37 and 57 and ground. If voltage is 10 volts or more, circuit is okay. Go to CIRCUIT TEST DLC. If voltage is less than 10 volts, go to next step.
2) Check VPWR Circuit Turn ignition off. Disconnect engine continuity relay connector, located in left engine compartment fuse panel. Measure resistance between breakout box test pins No. 6, 37 and 57 and VPWR terminal of engine continuity relay harness connector. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair VPWR circuit.
3) Check Power To Relay Leave engine continuity relay disconnected. Turn ignition on. Measure voltage between PWR terminal at engine cont relay harness connector and ground. If voltage is greater than 10 volts, go to next step. If voltage is less than 10 volts, check 25-amp ENGINE CONT fuse. If fuse is okay, repair PWR circuit as necessary.
4) Check Ground At Relay Leave engine continuity relay harness connector disconnected. Turn ignition on. Measure voltage between PWR and GND terminals at engine continuity relay harness connector. If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, repair GND circuit.
5) Check Engine Cont Relay Remove engine continuity relay. Check for continuity between terminals No. 3 (PWR) and No. 4 (VPWR). Apply battery voltage between terminals No. 1 (PWR) and No. 2 (GND). (Scheme 19) Again, check for continuity between terminals No. 3 and 4. Continuity should be present when battery voltage is applied and not present when battery voltage is removed. If continuity is as specified, go to next step. If continuity is not as specified, replace engine continuity relay.
6) Check Ground At PCM Ensure ignition is off and PCM is disconnected from breakout box. Measure resistance between breakout box test pin No. 44 and ground. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair GND circuit.
Engine Cont Relay Connector Terminal ID. Scheme 19
Perform this test when directed by another CIRCUIT TEST. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuit (VREF and SIGRTN).
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| VREF | 37 | 26 | Brown |
| SIGRTN | 21 & 29 | 46 | White/Black |
| (1) Rotunda Breakout Box (007-00033). | |||
| (1) | Rotunda Breakout Box (007-00033). |
VREF CIRCUIT INFORMATION
1) Check VREF At PCM Turn ignition off. Install Breakout Box (007-00033). Connect PCM to breakout box. Turn ignition on. Measure voltage between breakout box test pins No. 26 (VREF) and No. 46 (SIGRTN). If voltage is 4-5 volts, go to next step. If voltage is not 4-5 volts, go to CIRCUIT TEST PGC.
2) Check VREF At TP Sensor Turn ignition off. Disconnect TP sensor wiring harness connector. Turn ignition on. Measure voltage between SIGRTN and VREF terminals at TP sensor harness connector. If voltage is 4-5 volts, circuit is okay and testing is complete. If voltage exceeds 10 volts, repair circuit short to power. If voltage is zero volts, go to next step.
3) Check VREF Circuit Turn ignition off. Disconnect PCM from breakout box. Leave TP sensor disconnected. Measure resistance between VREF terminal at TP sensor harness connector and test pin No. 26 at breakout box. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open in VREF circuit.
4) Ensure ignition is off. Measure resistance between test pin No. 26 at breakout box and ground. If resistance is 10,000 ohms or more, repair TP sensor SIGRTN circuit. If resistance is less than 10,000 ohms, repair short in VREF circuit.
Perform this test when directed by QUICK TEST or another test procedure. This CIRCUIT TEST is intended to diagnose
- Wiring harness circuit VSS.
Identifying VSS Circuit & Connector Terminals. Scheme 20
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color |
|---|---|---|---|
| VSS | 32 | 3 | (2) Green/Yellow |
| GND | N/a | N/a | Black/Red |
| (1) Rotunda Breakout Box (007-00033). (2) This wire color may also be Pink/Blue. | |||
| (1) | Rotunda Breakout Box (007-00033). |
| (2) | This wire color may also be Pink/Blue. |
VSS CIRCUIT INFORMATION
1) Check VSS Circuit Turn ignition off. Disconnect instrument cluster harness connector. Install Breakout Box (007-00033), leaving PCM disconnected. Measure resistance between breakout box test pin No. 3 and VSS terminal at instrument cluster harness connector. If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair VSS circuit.
2) Leave ignition off and instrument cluster harness connector disconnected. Measure resistance between breakout box test pin No. 3 and ground. If resistance is less than 10,000 ohms, repair VSS circuit. If resistance is 10,000 ohms or more, verify speedometer is functioning normally. If speedometer is okay, go to next step.
3) Leave ignition off and instrument cluster harness connector disconnected. Disconnect vehicle speed sensor wiring harness connector. Measure resistance of Pink/Blue wire between VSS harness connector and terminal VEHICLE SPEED SENSOR INPUT SIGNAL TO CLUSTER (Pink/Blue wire) of instrument cluster harness connector. Resistance should be less than 5 ohms. Measure resistance between terminal VEHICLE SPEED SENSOR INPUT SIGNAL TO CLUSTER (Pink/Blue wire) of instrument cluster harness connector and ground. Resistance should be more than 10,000 ohms. If resistance is as specified, go to next step. If resistance is not as specified, repair Pink/Blue wire circuit.
4) Check VSS Output Leave ignition off. Remove vehicle speed sensor from transaxle. Set voltmeter on AC range. Connect voltmeter positive test lead to vehicle speed sensor Pink/Blue terminal and negative test lead to Black/Red terminal. Turn vehicle speed sensor pinion gear while measuring voltage output. If voltage is about 0.5 volt, replace PCM. If voltage is not about 0.5 volt, replace vehicle speed sensor.