Pinpoint Test A: The Engine Does Not Crank
Starting System
Pinpoint Tests
Pinpoint Test A: The Engine Does Not Crank
Refer to Wiring Diagram Set 20, Starting System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, constant power is supplied to the starter motor relay from the Battery Junction Box (BJB) fuse 41 (30A). When the ignition switch is turned in the START position and held, with the vehicle in PARK or NEUTRAL, power flows to the starter motor relay through CDC35 (BU/WH). A ground is supplied through circuit CDC12 (YE) from the PCM causing the starter motor relay coil to energize and the relay contacts close. This allows power to be supplied from the starter motor relay contacts which then flows through circuit CDC25 (BN/GN) to the starter solenoid. The solenoid is grounded at the starter motor. Energizing the starter solenoid will engage the starter drive into the ring gear and closes the solenoid contacts allowing power directly from the battery through circuit SDC02 (RD) to the starter motor to start the engine.
This pinpoint test is intended to diagnose the following:
- Battery
- Anti-theft system
- Starter relay
- Ignition switch
- Circuitry
- PCM
- Start diode
PINPOINT TEST A: THE ENGINE DOES NOT CRANK
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A1 CHECK THE BATTERY
- Check the battery condition and state of charge. Refer to Diagnosis and Testing in Battery. Testing and Inspection
- Is the battery OK?
Yes
GO to A2.
No
CHARGE or INSTALL a new battery as necessary. REFER to Battery. TEST the system for normal operation.
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A2 CHECK FOR PCM DTCs
- Check for PCM DTCs.
- Were any PCM DTCs retrieved?
Yes
If PCM DTC P1260 is retrieved, REFER to Antitheft and Alarm Systems. All other PCM DTCs, REFER to Computers and Control Systems Information.
No
GO to A3.
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A3 CHECK THE PCM TR SENSOR PID
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger - PCM.
- While observing the Transmission Range (TR) sensor PID, place the vehicle in PARK and NEUTRAL.
- Does the PID match the gear selection?
Yes
GO to A4.
No
GO to the appropriate automatic transmission system to diagnose the TR sensor.
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A4 CHECK THE PCM STARTER MOTOR CONTROL OUTPUT DETECTED (SMC_MON) PID
- Enter the following diagnostic mode on the scan tool: DataLogger - PCM.
- Monitor the SMC_MON PID with the ignition switch in the START position.
- Does the PID change from OFF to ON?
Yes
GO to A5.
No
GO to A12.
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A5 CHECK THE PCM STARTER MOTOR RELAY ENABLE (STRT_RLY) PID
- Enter the following diagnostic mode on the scan tool: DataLogger - PCM.
- Monitor the STRT_RLY PID with the ignition switch in the START position.
- Does the PID change from DISABLED to ENABLED?
Yes
GO to A6.
No
GO to A21.
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A6 CHECK STARTER MOTOR RELAY POWER
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
- Disconnect: Starter Motor Relay.
- Measure the voltage between BJB starter motor relay pin 30, harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to A7.
No
VERIFY BJB fuse 41 (30 A) is OK. If OK, REPAIR circuit SCD02 (RD). TEST the system for normal operation. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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A7 CHECK THE BATTERY GROUND CABLE
- Measure the voltage between the positive battery post and the battery ground cable connection at the engine.
- Is the voltage greater than 10 volts?
Yes
GO to A8.
No
INSTALL a new battery ground cable. REFER to Battery. TEST the system for normal operation.
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A8 CHECK THE STARTER MOTOR GROUND
- Measure the voltage between the positive battery post and the starter motor case.
- Is the voltage greater than 10 volts?
Yes
GO to A9.
No
CLEAN the starter motor mounting flange and make sure the starter motor is correctly mounted. TEST the system for normal operation.
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A9 CHECK THE POWER SUPPLY TO THE STARTER MOTOR
- Measure the voltage between starter motor C197A, circuit SDC02 (RD) and ground.
- Is the voltage greater than 10 volts?
Yes
GO to A10.
No
INSTALL a new positive battery cable. REFER to Battery. TEST the system for normal operation.
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A10 CHECK THE STARTER MOTOR B-PIN
- Connect one end of a fused jumper wire to starter motor solenoid C197A, circuit SDC02 (RD). Momentarily connect the other end of the jumper to starter motor C197B, circuit CDC25 (BN/GN).
- Did the starter motor engage and the engine crank?
Yes
GO to A11.
No
INSTALL a new starter motor. REFER to Starter Motor Service and Repair. TEST the system for normal operation.
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A11 CHECK THE CIRCUIT TO THE STARTER MOTOR
- Ignition OFF.
- Disconnect: Starter Motor Relay.
- Disconnect: Starter Motor Solenoid C197B.
- Measure the resistance between starter motor solenoid S-terminal C197B, circuit CDC25 (BN/GN), harness side and the BJB starter motor relay pin 87, circuit CDC25 (BN/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new starter motor relay. TEST the system for normal operation.
No
REPAIR circuit CDC25 (BN/GN). TEST the system for normal operation.
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A12 CHECK STARTER MOTOR RELAY POWER
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
- Disconnect: Starter Motor Relay.
- Measure the voltage between BJB starter motor relay pin 30, harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to A13.
No
VERIFY BJB fuse 41 (30 A) is OK. If OK, REPAIR circuit SCD02 (RD). TEST the system for normal operation. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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A13 CHECK THE STARTER MOTOR RELAY
- Carry out the Starter Motor Relay Component Test.
- Did the starter motor relay pass the component test?
Yes
GO to A14.
No
INSTALL a new starter motor relay. TEST the system for normal operation.
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A14 CHECK THE START DIODE
- Disconnect: Start Diode.
- Check the start diode for an open or shorted condition.
- Is the start diode OK?
Yes
GO to A15.
No
INSTALL a new start diode. TEST the system for normal operation.
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A15 CHECK THE START SIGNAL TO THE STARTER MOTOR RELAY
- Measure the voltage between the BJB starter motor relay pin 85, circuit CDC35 (BU/WH), harness side and ground with the ignition switch in the START position.
- Is the voltage greater than 10 volts?
Yes
GO to A19.
No
GO to A16.
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A16 CHECK CIRCUIT CDC35 (BU/WH) FOR AN OPEN BETWEEN START DIODE AND STARTER RELAY
- Disconnect: Start Diode.
- Measure the resistance between the start diode cell, circuit CDC35 (BU/WH), harness side and BJB starter motor relay pin 85, circuit CDC35 (BU/WH), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to A17.
No
REPAIR circuit CDC35 (BU/WH) for an open. TEST the system for normal operation.
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A17 CHECK CIRCUIT SBP27 (BU/RD) FOR VOLTAGE
- Disconnect: Ignition Switch C250.
- Measure the voltage between ignition switch C250-4, circuit SBP27 (BU/RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to A18.
No
REPAIR circuit SBP27 (BU/RD). TEST the system for normal operation.
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A18 CHECK THE IGNITION SWITCH
- Carry out the Ignition Switch Component Test.
- Did the ignition switch pass the component test?
Yes
REPAIR circuit CDC35 (BU/WH) for an open. TEST the system for normal operation.
No
INSTALL a new ignition switch. REFER to Steering Column. TEST the system for normal operation.
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A19 CHECK CIRCUIT CDC35 (BU/WH) FOR AN OPEN
- Connect: Starter Motor Relay.
- Disconnect: PCM C175B.
- Disconnect: Start Diode.
- Measure the resistance between the start diode cell, circuit CDC35 (BU/WH), harness side and PCM C175B-9, circuit CDC35 (BU/WH), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to A20.
No
REPAIR circuit CDC35 (BU/WH) for an open. TEST the system for normal operation.
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A20 CHECK THE CIRCUIT CDC35 (BU/WH) BETWEEN THE BJB AND THE PCM
- Ignition OFF.
- Disconnect: Starter Motor Relay.
- Disconnect: Smart Junction Box (SJB) C2280B.
- Measure the resistance between the BJB starter motor relay pin 85, circuit CDC35 (BU/WH), harness side and PCM C175B-35, circuit CDC35 (BU/WH), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new PCM. REFER to Computers and Control Systems. TEST the system for normal operation.
No
REPAIR circuit CDC35 (BU/WH). TEST the system for normal operation.
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A21 CHECK THE STARTER MOTOR RELAY
- Carry out the Starter Motor Relay Component Test.
- Did the starter motor relay pass the component test?
Yes
GO to A22.
No
INSTALL a new starter motor relay. TEST the system for normal operation.
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A22 CHECK CIRCUIT CDC12 (YE) FOR AN OPEN
- Disconnect: PCM C175B.
- Measure the resistance between the BJB starter relay pin 86, circuit CDC12 (YE), harness side and PCM C175B-34, circuit CDC12 (YE), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new PCM. REFER to Computers and Control Systems.
No
REPAIR circuit CDC12 (YE). TEST the system for normal operation.
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