Procedure 2 - Tachometer Inoperative
Tachometer does not Work.Tachometer Circuit:
Connectors:
CIRCUIT OPERATION
- The tachometer power is supplied from the ignition switch (IG) circuit.
- For vehicles with 2.4L engine, the tachometer detects the ignition signal by the engine control module via the ignition coils.
- For vehicles with 3.0L engine, the tachometer detects the ignition signal control via the distributor assembly.
TECHNICAL DESCRIPTION (COMMENT)
The ignition signal may not be sent from the engine, or there may be a malfunction in the power supply or ground circuit.
TROUBLESHOOTING HINTS
- Malfunction of the combination meter (printed circuit board or speedometer and tachometer)
- Damaged harness wires or connectors
- Malfunction of the PCM
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB991502: Scan Tool (MUT-II)
STEP 1. Check the MFI system
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Read the MFI system diagnostic trouble code.
Q: Is MFI system DTC P0300 output?
YES: Check the MFI system, Go to Step 9,.
NO: Go to Step 2.
STEP 2. Check the speedometer operation.
Q: Does the speedometer work normally?
YES: Refer to Inspection Procedure 1.
NO: Go to Step 3.
STEP 3. Check the combination meter (tachometer) ground circuit at the combination meter connector C-29.
1. Disconnect the combination meter connector C-29.
2. Measure the resistance between terminal 30 and ground.
Q: Is the resistance less than 2 ohm?
YES: Go to Step 6.
NO: Go to Step 4.
STEP 4. Check the combination meter connector C-29 for damage.
Q: Is combination meter connector C-29 in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Refer to Harness Connector Inspection. The tachometer should work normally.
STEP 5. Check the harness wires between combination meter connector C-29 and ground.
Q: Is the harness wires between combination meter connector C-29 and ground in good condition?
YES: There is no action to be taken.
NO: Repair it. The tachometer should work normally.
STEP 6. Check the ignition signal input circuit at the combination meter connector C-30.
1. Disconnect the combination meter connector C-30.
2. Start the engine and run at idle.
3. Measure the voltage between terminal 15 and ground.
Q: Is the voltage approximately 10 volts?
YES: Repair or replace the combination meter (printed-circuit board or speedometer and tachometer).
NO: Go to Step 7.
STEP 7. Check the PCM connector C-40 <2.4L>, distributor assembly connector B-27 <3.0L>, automatic compressor controller connector C-16 <3.0L> and combination meter connector C-30 for damage.
Q: Are PCM connector C-40 <2.4L> distributor assembly connector B-27 <3.0L>, automatic compressor controller connector C-16 <3.0L> and combination meter connector C-30 in good condition?
YES: Go to Step 8.
NO: Repair or replace them. Refer to Harness Connector Inspection. The tachometer should work normally.
STEP 8. Check the harness wires from combination meter connector C-30 to PCM connector C-40 <2.4L>, distributor assembly connector B-27 <3.0L> and automatic compressor controller connector C-16 <3.0L>.
NOTE: After checking intermediate connector C-17, check the wires. If intermediate connector C-17 is damaged, repair or replace it. Refer to Harness Connector Inspection.
Q: Are the harness wires from combination meter connector C-30 to PCM connector C-40 <2.4L> distributor assembly connector B-27 <3.0L> and automatic compressor controller connector C-16 <3.0L> in good condition?
YES: There is no action to be taken.
NO: Repair it. The tachometer should work normally.
STEP 9. Using scan tool MB991502, check data list item 22: Crankshaft Position Sensor.
1. Start the engine and run at idle.
2. Set scan tool MB991502 to the data reading mode for item 22, Crankshaft Position Sensor.
3. Check the waveform of the crankshaft position sensor while keeping the engine speed constant.
- The pulse width should be constant.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 10.
NO: Refer to Computers and Control Systems/Testing, MFI - MFI Diagnosis.
STEP 10. Using scan tool MB991502, check data list item 81: Long - Term Fuel Compensation (trim).
1. Start the engine and run at idle.
2. Set scan tool MB991502 to the data reading mode for item 81: Long - Term Fuel Compensation (trim).
- The fuel trim should be between -12.5 and +12.5 when the load is 2,500 r/min (during closed loop) after the engine is warmed.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the specification normal?
YES: Go to Step 11.
NO: Refer to Computers and Control Systems/Testing, MFI - MFI Diagnosis.
STEP 11. Using scan tool MB991502, check data list item 82: Short - Term Fuel Compensation (trim).
1. Start the engine and run at idle.
2. Set scan tool MB991502 to the data reading mode for item 82. Short-Term Fuel Compensation (trim).
- The fuel trim should be between -25 and +16.8 when the load is 2,500 r/min (during closed loop) after the engine is warmed.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the specification normal?
YES: Go to Step 12.
NO: Refer to <2.4L>, MFI - MFI Diagnosis or <3.0L>, MFI - MFI Diagnosis.
STEP 12. Check the ignition coil spark
1. Check each ignition coil spark.
2. Remove the intake manifold.
3. Remove the spark plug and connect to the spark plug cable.
4. Ground the spark plug side electrode securely.
- When the engine is cranked, the spark plug should spark.
Q: Did it spark?
YES: Go to Step 15.
NO: Go to Step 13.
STEP 13. Check the spark plugs.
CAUTION: Do not attempt to adjust the gap of the platinum plug. Cleaning of the platinum plug may result in damage to the platinum tips. Therefore, if carbon deposits must be removed, use a plug cleaner and complete cleaning within 20 seconds to protect the electrode. Do not use a wire brush.
1. Check the plug gap and replace if the limit is exceeded.
Standard value: 1.0 - 1.1 mm (0.039 - 0.043 inch)
Limit: 1.3 mm (0.051 inch)
Q: Is the plug gap at the standard value?
YES: Go to Step 14.
NO: Replace the faulty spark plug. Then go to Step 1.
STEP 14. Check the spark plug cable.
1. Check the cap and coating for cracks.
2. Measure the resistance.
Limit: maximum 22 kohm
Q: Is the resistance normal?
YES: Refer to Computers and Control Systems/Testing, MFI - MFI Diagnosis.
NO: Replace the faulty spark plug cable. Then go to Step 1.
STEP 15. Check the injector.
1. Disconnect the injector connector.
2. Measure the resistance between each injector side connector terminal 1 and 2.
Standard value: 13 - 16 ohm [at 20°C (68°F)]
Q: Is the resistance standard value?
YES: Go to Step 16.
NO: Replace the faulty injector. Then go to Step 1.
STEP 16. Check connector at injector for damage.
Q: Is the connector in good condition?
YES:
- Go to Step 17 <2.4L>.
- Go to Step 20 <3.0L>.
NO: Repair or replace the faulty injector. Refer to Harness Connector Inspection. Then go to Step 1.
STEP 17. Check connector C-39 at PCM and ignition coil connector B-09 and B-23 for damage <2.4L>.
Q: Is the connector in good condition?
YES: Go to Step 18.
NO: Refer to Computers and Control Systems/Testing, MFI - MFI Diagnosis.
STEP 18. Check for harness damage between ignition coil B-009, B-23 and PCM connector C-39.
Q: Is the harness wire in good condition?
YES: Go to Step 19.
NO: Repair it. Then go to Step 1.
STEP 19. Check the following items.
1. Check the following items, and repair or replace the defective component.
a. Check for skipped timing belt teeth.
b. Check compression.
c. EGR valve failed.
Q: Are there any abnormalities?
YES: Go to Step 20.
NO: Repair or replace it. Then go to Step 1.
STEP 20. Replace the injector.
1. Replace the injector.
2. Carry out a test drive with the drive cycle pattern.
3. Check the diagnostic trouble code (DTC).
Q: Is the DTC P0300 is output?
YES: Replace the ECM or PCM. Then go to Step 1.
NO: The inspection is complete.