Diagnostic Aids
Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used to diagnose the following:
- Crankshaft Position (CKP) Sensor
- Wiring Harness Circuits (CKP+ & CKP-)
- Powertrain Control Module (PCM)
- 1) Check CKP(+) & CKP(-) Circuit For Continuity
Turn ignition switch to OFF position. Disconnect CKP sensor and PCM connector(s). Inspect connectors for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of CKP(+) and CKP(-) circuits between PCM harness connector and CKP sensor harness connector. See Fig 1. If both resistance measurements are 5 ohms or less, go to next step. If either resistance measurement is more than 5 ohms, repair open in affected circuit. - 2) Check For CKP(+) Bias Voltage Fault
Reconnect PCM harness connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and CKP sensor harness connector CKP(+) terminal. If voltage is more than one volt, but less than 2 volts, go to next step. If voltage is not as specified, check for bias fault. Go to step 19). - 3) Check For CKP(-) Bias Voltage Fault
Ensure ignition switch is turned to ON position. Using a DVOM, measure voltage between negative battery terminal and CKP sensor harness connector CKP(-) terminal. If voltage is 1-2 volts, go to step 10). If voltage is not 1-2 volts, check for bias fault. Go to next step. - 4) Determine If Fault Is Bias High Or Bias Low
If voltage measurement in step 3) is less than one volt, fault is bias low. Go to next step. If voltage measurement in step 3) is 2 volts or more, fault is bias high. Go to step 6). - 5) Check CKP(-) Circuit For Short To Ground In Harness
Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance between negative battery terminal and PCM harness connector CKP(-) circuit terminal. See Fig 1. If resistance is more than 10 k/ohms, replace PCM. If resistance is 10 k/ohms or less, repair short to GND in CKP(-) circuit. - 6) Check CKP(-) Circuit For Short To PWR In Harness
Turn ignition switch to OFF position. Disconnect PCM connector(s). Turn ignition switch to ON position. Using a DVOM, measure voltage of CKP(-) circuit between negative battery terminal and PCM harness connector. If voltage is .5 volt or more, repair short to PWR in CKP(-) circuit. If resistance is less than .5 volt, replace PCM.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. - 10) Check CKP Sensor Amplitude At PCM
Turn ignition switch to OFF position. Reconnect CKP sensor connector. Disconnect PCM connector(s). While cranking engine, measure voltage between PCM harness connector CKP(+) and CKP(-) circuit terminals. See Fig 1. If A/C voltage stabilized at more than .4 volt, CKP circuit is okay, go to next step. If voltage is .4 volt or less, amplitude fault exists. Go to step 12). - 11) Check CKP(+) Circuit For Short To Ground At Sensor
Using a DVOM, measure resistance between negative battery terminal and backprobing CKP sensor harness connector CKP(+) terminal. If resistance is more than 10 k/ohms, go to TEST JB, step 1) . If resistance is 10 k/ohms or less, go to step 17). - 12) Check CKP Circuit Resistance For Amplitude Fault
Turn ignition switch to OFF position. Ensure PCM is disconnected. Using a DVOM, measure resistance between PCM harness connector CKP(+) and CKP(-) terminals. If resistance is 300-800 ohms, go to step 16). If resistance is not as specified, go to next step. - 13) Determine High Or Low Resistance Fault
If resistance is less than 300 ohms in step 12), low resistance fault exists. Go to next step. If resistance is more than 800 ohms, replace CKP sensor. - 14) Check For Short Between CKP(+) & CKP(-)
Disconnect CKP sensor connector. Using a DVOM, measure resistance between CKP sensor harness connector terminals. If resistance is less than 5 ohms, repair short between CKP(+) and CKP(-) circuits. If resistance is 5 ohms or more, replace CKP sensor.NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 14) to step 16). No test procedures have been omitted. - 16) Check CKP Sensor & Pulse Wheel
Check CKP sensor and pulse wheel for damage. Repair as necessary. If CKP sensor and pulse wheel are okay, replace CKP sensor. - 17) Check For PCM Fault
Turn ignition switch to OFF position. Disconnect CKP sensor connector. Reconnect PCM harness connector. Using a DVOM, measure resistance between CKP sensor harness connector terminals. If resistance is 16,000-24,000 ohms, go to next step. If resistance is not 16,000-24,000 ohms, replace PCM. - 18) Check CKP(+) Circuit For Short To CKP(-) Circuit
Ensure CKP sensor is disconnected. Disconnect PCM connector(s). Using a DVOM, measure resistance between PCM harness connector CKP(+) and CKP(-) terminals. See Fig 1. If resistance is more than 1000 ohms, replace CKP sensor. If resistance is 1000 ohms or less, repair short between CKP(+) and CKP(-) circuits. - 19) Determine If Fault Is Bias High Or Bias Low
If voltage measurement in step 2) is less than one volt, low bias voltage fault exists. Go to next step. If voltage measurement in step 2) is 2 volts or more, high bias voltage fault exists. Go to step 21). - 20) Check CKP(+) Circuit For Short To GND In Harness
Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance between negative battery terminal and PCM harness connector CKP(+) terminal. See Fig 1. If resistance is more than 10 k/ohms, replace PCM. If resistance is 10 k/ohms or less, repair short to GND in CKP(+) circuit. - 21) Check CKP(+) Sensor For Short To PWR
Turn ignition switch to OFF position. Disconnect PCM connector(s). Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and PCM harness connector CKP(+) terminal. If voltage is .5 volt or more, repair short to PWR in CKP(+) circuit. If voltage is less than .5 volt, replace PCM.