DTC 21

DTC 21: Crankshaft Position Sensor System




















CIRCUIT OPERATION
The crankshaft position sensor power is supplied from the MFI relay (terminal 3), and the ground (terminal 1) is provided on the vehicle body. The PCM supplies a five-volts voltage to crankshaft position sensor output terminal (terminal 2). The crankshaft position sensor generates a pulse signal when the output terminal is opened and grounded. The sensor is opened and closed as the flat on the crankshaft passes by.

DTC SET CONDITIONS
If no output pulse is detected from the crankshaft position sensor for five seconds or more while driving at 25 km/h (16 mph) or more, it is judged that there is an open circuit in the crankshaft position sensor and diagnostic trouble code number "21" is sent.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set:)
- Malfunction of the crankshaft position sensor circuit
- Damaged harness, connector
- Malfunction of the PCM

DIAGNOSIS

Required Special Tool:
- MB991502: Scan Tool (MUT-II)

CAUTION: To prevent damage to the scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting the scan tool MB991502.

STEP 1. Using scan tool MB991502, check data list item 21: Crankshaft Position Sensor.

CAUTION: To prevent damage to the scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting the scan tool MB991502.





1) Connect scan tool MB991502 to the data link connector.
2) With the gear selector lever in the "P" position, start the engine and run at idle.
3) Set scan tool MB991502 to the data reading mode for item 21: Crankshaft Position Sensor.
- When the accelerator pedal is not depressed (throttle valve is fully closed) the display should be "600 to 900 r/min."
- With the accelerator pedal depressed, the engine speed should increase according to engine speed.

Q: Is the sensor operating properly?
YES: This malfunction is intermittent.
NO: Go to Step 2.
STEP 2. Using the oscilloscope, check the waveform at crankshaft position sensor connector B-20.








1) Do not disconnect the crankshaft position sensor connector B-20.





2) Connect an oscilloscope probe to the crankshaft position sensor connector terminal 2 by backprobing.
3) With the gear selector lever in the "P" position, start the engine and run at idle.





4) Check the waveform.
- The waveform should show a pattern similar to the illustration. The maximum value should be 4.8 volts and more and the minimum value 0.6 volts and less.

5) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is the waveform normal?
YES: Go to Step 3.
NO: Go to Step 5.











STEP 3. Check connector B-20 at the crankshaft position sensor and C-114 <2.4L Engine> or C-115 <3.0L Engine> at PCM for damage.
Q: Are the connectors in good condition?
YES: Go to Step 4.
NO: Repair or replace it.
STEP 4. Using scan tool MB991502, check data list item 21: Crankshaft Position Sensor.

CAUTION: To prevent damage to the scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting the scan tool MB991502.





1) Connect scan tool MB991502 to the data link connector.
2) With the gear selector lever in the "P" position, start the engine and run at idle.
3) Set scan tool MB991502 to the data reading mode for item
21: Crankshaft Position Sensor.
- When the accelerator pedal is not depressed (throttle valve is fully closed) the display should be "600 to 900 r/ min."
- With the accelerator pedal depressed, the engine speed should increase according to engine speed.

Q: Is the sensor operating properly?
YES: This malfunction is intermittent.
NO: Replace the PCM.








STEP 5. Check connector B-20 at the crankshaft position sensor for damage.
Q: Is the connector in good condition?
YES: Go to Step 6.
NO: Repair or replace it.
STEP 6. Check the sensor output voltage at crankshaft position sensor connector B-20.








1) Disconnect connector B-20 and measure at the harness side.
2) Turn the ignition switch to the "ON" position.





3) Measure the voltage between terminal 2 and ground.
- Voltage should be between 4.8 and 5.2 volts.

4) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is the voltage normal?
YES: Go to Step 11.
NO: Go to Step 7.
STEP 7. Check the sensor output voltage at PCM connector C-114 <2.4L Engine> or C-115 <3.0L Engine> by backprobing.





1) Do not disconnect connector C-114 <2.4L Engine> or C-115 <3.0L Engine>.
2) Disconnect connector B-20 at the crankshaft position sensor.
3) Turn the ignition switch to the "ON" position.





4) Measure the voltage between terminal 45 and ground by backprobing.
- Voltage should be between 4.8 and 5.2 volts.

5) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is the voltage normal?
YES: Go to Step 8.
NO: Go to Step 9.





STEP 8. Check connector C-114 <2.4L Engine> or C-115 <3.0L Engine> at PCM for damage.
Q: Is the connector in good condition?
YES: Repair it because of harness open circuit between crankshaft position sensor connector B-20 terminal 2 and PCM connector C-114 <2.4L Engine> or C-115 <3.0L Engine> terminal 45.
NO: Repair or replace it.





STEP 9. Check connector C-114 <2.4L Engine> or C-115 <3.0L Engine> at PCM for damage.
Q: Is the connector in good condition?
YES: Go to Step 10.
NO: Repair or replace it.











STEP 10. Check harness for short circuit to ground between crankshaft position sensor connector B-20 terminal 2 and PCM connector C-114 <2.4L Engine> or C115 <3.0L Engine, terminal 45.
Q: Is the harness wire in good condition?
YES: Go to Step 4.
NO: Repair it.
STEP 11. Check the power supply voltage at crankshaft position sensor connector B-20.








1) Disconnect connector B-20 and measure at the harness side.
2) Turn the ignition switch to the "ON" position.





3) Measure the voltage between terminal 3 and ground.
- Voltage should be battery positive voltage.

4) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is the voltage normal?
YES: Go to Step 13.
NO: Go to Step 12.





STEP 12. Check connector B-21X at MFI relay for damage.
Q: Is the connector in good condition?
YES: Repair it because of harness open circuit or short circuit to ground between MFI relay connector B-21X terminal 1 and crankshaft position sensor connector B-20 terminal 3.
NO: Repair or replace it.
STEP 13. Check the continuity at crankshaft position sensor connector B-20.








1) Disconnect connector B-20 and measure at the harness side.





2) Check for the continuity between terminal 1 and ground.
- Should be less than 2 ohm.

Q: Is the continuity normal?
YES: Go to Step 14.
NO: Repair it because of harness open circuit or damage between crankshaft position sensor connector B-20 terminal 1 and ground.








STEP 14. Check connectors C-114 <2.4L Engine> or C-115 <3.0L Engine> at PCM and A-21X at the MFI relay for damage.
Q: Are the harness connectors in good condition?
YES: Go to Step 15.
NO: Repair or replace it.











STEP 15. Check harness for damage between crankshaft position sensor connector B-20 terminal 2 and PCM connector C-114 <2.4L Engine> or C-115 <3.0L Engine> terminal 45.
Q: Is the harness wire in good condition?
YES: Go to Step 16.
NO: Repair it.











STEP 16. Check harness for damage between MFI relay connector B-21X terminal 1 and crankshaft position sensor connector B-20 terminal 3.
Q: Is the harness wire in good condition?
YES :Go to Step 17.
NO: Repair it.








STEP 17. Check harness for damage between crankshaft position sensor connector B-20 terminal 1 and ground.
Q: Is the harness wire in good condition?
YES: Go to Step 18.
NO: Repair it.
STEP 18. Check the crankshaft position sensor vane.
Q: Is the vane in good condition?
YES: Replace the crankshaft position sensor.
NO: Repair it.