Pinpoint Test A: The Engine Does Not Crank
Starting System
Pinpoint Test A: The Engine Does Not Crank
Refer to Wiring Diagram Set 20, Starting System for schematic and connector information [1][2]Diagrams By Number.
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
Normal Operation
When the ignition switch is turned to the START position, the PCM receives a starter motor request signal. Voltage is supplied to the starter relay from the PCM. The PCM receives a signal from the digital Transmission Range (TR) sensor that the vehicle is in PARK or NEUTRAL (vehicles equipped with an automatic transmission) or from the Clutch Pedal Position (CPP) switch when the clutch pedal is fully depressed (vehicles equipped with manual transmission). A ground is supplied from the PCM causing the starter relay coil to energize and the relay contacts to close. This allows voltage to be supplied from Battery Junction Box (BJB) fuse 19 (30A) to the relay contacts, which then flows to the starter solenoid. The solenoid is grounded at the starter motor. Energizing the starter solenoid engages the starter drive into the ring gear and closes the solenoid contacts allowing voltage directly from the battery to the starter motor to start the engine. The PCM will disengage the starter motor based on engine running (rpm threshold), a set crank time has been exceeded or the ignition switch has been turned to the OFF position.
- DTC P0512 (Starter Request Circuit)- this DTC sets when the PCM detects an open or short to ground on the starter request circuit.
This pinpoint test is intended to diagnose the following:
- Anti-theft system
- Fuse
- Battery
- Battery cables
- Wiring, terminals or connectors
- CPP (Clutch Pedal Position) (manual transmission)
- Ignition switch
- PCM
- Starter motor
- Starter motor relay
- Digital TR (Transmission Range) sensor (automatic transmission)
PINPOINT TEST A : THE ENGINE DOES NOT CRANK
A1 CHECK THE BATTERY
- Check the battery condition and charge.
Is the battery OK?
Yes
GO to A2.
No
CHARGE or INSTALL a new battery. TEST the system for normal operation.
A2 CHECK THE PCM FOR DTCs
- Using the DTCs retrieved in Inspection and Verification, check for Passive Anti-Theft System (PATS) and PCM DTCs.
Were any PCM DTCs retrieved?
Yes
If DTC P0512 is retrieved, GO to A14.
If PCM DTC P1260 is retrieved, REFER to Antitheft and Alarm Systems. All other PCM DTCs, REFER to Computers and Control Systems.
No
For automatic transmissions,GO to A3.
For manual transmissions,GO to A4.
A3 CHECK THE PCM TR (Transmission Range) SENSOR PID
- Enter the following diagnostic mode on the scan tool: DataLogger- PCM.
- While observing the TR (Transmission Range) PID, place the vehicle in PARK and then NEUTRAL.
Does the PID match the gear selection?
Yes
GO to A5.
No
REFER to Automatic Transmission/Transaxle &/or Transmission Control Systems, to diagnose the TR (Transmission Range) sensor.
A4 CHECK THE PCM CLUTCH PEDAL AT OR NEAR BOTTOM OF TRAVEL (CPP_ BOT) PID
- Enter the following diagnostic mode on the scan tool: DataLogger- PCM.
- While observing the CPP_ BOT PID, fully disengage the clutch.
Does the PID change from NO to YES?
Yes
GO to A5.
No
GO to A18.
A5 CHECK THE PCM STARTER MOTOR RELAY ENABLE (STRT_RLY) PID
- NOTE: For manual transmission, fully disengage the clutch
Monitor the STRT_RLY PID while holding the key in the START position.
Does the PID change from DISABLED to ENABLED?
Yes
GO to A6.
No
GO to A16.
A6 CHECK THE STARTER MOTOR RELAY
- Swap the starter relay with a known good relay and attempt to crank the engine.
Does the engine crank?
Yes
INSTALL a new starter relay. TEST the system for normal operation.
No
GO to A7.
A7 CHECK THE VOLTAGE TO THE STARTER MOTOR RELAY
- Ignition OFF.
- Disconnect: Starter Motor Relay.
- Measure the voltage between Battery Junction Box (BJB) starter relay socket, pin 30, circuit SBB19 (BU/RD), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to A8.
No
VERIFY BJB (Battery Junction Box) fuse 19 (30A) is OK. If OK, REPAIR circuit SBB19 (BU/RD) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short [1][2]Diagrams By Number.
A8 CHECK THE STARTER MOTOR
- Connect one end of a fused jumper wire to BJB (Battery Junction Box) starter relay socket, pin 30, circuit SBB19 (/BURD) and momentarily connect the other end of the fused jumper wire to BJB (Battery Junction Box) starter relay socket, pin 87, circuit CDC25 (BN/GN).
Did the starter motor engage and the engine crank?
Yes
GO to A14.
No
GO to A9.
A9 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 A10.
No
INSTALL a new battery ground cable. TEST the system for normal operation.
A10 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 A11.
No
CLEAN the starter motor mounting flange and make sure the starter motor is correctly mounted. TEST the system for normal operation.
A11 CHECK THE VOLTAGE 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 A12.
No
INSTALL a new positive battery cable. TEST the system for normal operation.
A12 CHECK THE STARTER MOTOR
- Connect one end of a fused jumper wire to starter motor solenoid C197A, circuit SDC02 (RD) and momentarily connect the other end of the fused jumper wire to starter motor solenoid C197B, circuit CDC25 (BN/GN).
Did the starter motor engage and the engine crank?
Yes
GO to A13.
No
INSTALL a new starter motor. REFER to Starter Motor - 3.7L or Starter Motor - 5.0L (4V) or Starter Motor - 5.4L (4V) . TEST the system for normal operation.
A13 CHECK FOR START INPUT AT THE STARTER
- Connect: Starter Motor Relay.
- Disconnect: Starter Solenoid C197B.
- Measure the voltage between the starter motor solenoid C197B-1, circuit CDC25 (BN/GN) and ground, while holding the key in the START position.
Is the voltage reading greater than 10 volts?
Yes
CLEAN the starter motor solenoid S-terminal and connector. CHECK the wiring and the starter motor for a loose or intermittent connection. TEST the system for normal operation.
No
REPAIR circuit CDC25 (BN/GN) for an open. TEST the system for normal operation.
A14 CHECK THE PCM START CIRCUITS FOR A SHORT TO GROUND
- Disconnect: Starter Motor Relay (if not previously disconnected).
- Disconnect: PCM Connector C175B or C1381B.
- Measure the resistance between PCM C175B OR C1381B, harness side and ground, using the following chart.
PCM Connector Circuit 5.0L and 5.4L ,C175B-7
3.7L,C1381B-7CDC12 (YE) 5.0L and 5.4L ,C175B-37
3.7L,C1381B-37CDC54 (WH/GN)
Are the resistances greater than 10,000 ohms?
Yes
GO to A15.
No
REPAIR the affected circuit for a short to ground. TEST the system for normal operation.
A15 CHECK THE PCM START CIRCUITS FOR AN OPEN
- Measure the resistance between PCM C175B OR C1381B, harness side and the BJB (Battery Junction Box) starter relay socket, using the following chart.
PCM Connector Circuit BJB (Battery Junction Box) 5.0L and 5.4L ,C175B-7
3.7L,C1381B-7CDC12 (YE) BJB (Battery Junction Box) starter relay socket, pin 85 5.0L and 5.4L ,C175B-37
3.7L,C1381B-37CDC54 (WH/GN) BJB (Battery Junction Box) starter relay socket, pin 86
Are the resistances less than 5 ohms?
Yes
INSTALL a new PCM. TEST the system for normal operation.
No
REPAIR the affected circuit for an open. TEST the system for normal operation.
A16 CHECK THE START CIRCUIT FOR VOLTAGE AT THE PCM
- Disconnect: PCM C175B or C1381B.
- Measure the voltage:
- For 5.0L and 5.4L , between PCM C175B-16, circuit CDC35 (BU/WH) and ground, while holding the key in the START position.
- For 3.7L, between PCM C1381B-16, circuit CDC35 (BU/WH) and ground, while holding the key in the START position.
Is the voltage greater than 10 volts?
Yes
INSTALL a new PCM. TEST the system for normal operation.
No
GO to A17.
A17 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 switch5. TEST the system for normal operation.
A18 CHECK THE BOTTOM OF TRAVEL CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: CPP (Clutch Pedal Position) Switch C257.
- Disconnect: PCM C175T or C1381T.
- For 5.0L and 5.4L , measure the resistance between CPP (Clutch Pedal Position) switch C257-1, circuit CE903 (BU/OG), harness side and PCM C175T-19, circuit CE903 (BU/OG), harness side.
- For 3.7L, measure the resistance between CPP (Clutch Pedal Position) switch C257-1, circuit CE903 (BU/OG), harness side and PCM C1381T-26, circuit CE903 (BU/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to A19.
No
REPAIR circuit CE903 (BU/OG) for an open. TEST the system for normal operation.
A19 CHECK THE CCP GROUND CIRCUIT FOR AN OPEN
- Measure the resistance between CPP switch C257-2, circuit GD129 (BK/YE), harness side and ground.
Is the resistance less than 5 ohms?
Yes
GO to A20.
No
REPAIR circuit GD129 (BK/YE) for an open. TEST the system for normal operation.
A20 CHECK THE CPP (Clutch Pedal Position) SWITCH
- Connect: CPP (Clutch Pedal Position) Switch C257.
- For 5.0L and 5.4L , measure the resistance between PCM C175T-19, circuit CE903 (BU/OG), harness side and ground while depressing the clutch pedal.
- For 3.7L, measure the resistance between PCM C1381T-26, circuit CE903 (BU/OG), harness side and ground while depressing the clutch pedal.
Is the resistance less than 5 ohms?
Yes
INSTALL a new PCM. TEST the system for normal operation.
No
INSTALL a new CPP (Clutch Pedal Position) switch. TEST the system for normal operation.