Inspection Procedure 2

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 failure sensor.
- 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

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991502: Scan Tool (MUT-II)

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




STEP 1. Check the vehicle speed sensor.
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: Refer to Computers/Testing.
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-102.
1. Disconnect the combination meter connector C-102.
2. Measure the resistance between terminal 27 and ground.

Q: Is the resistance less than 2 ohms?

YES: Go to Step 6.
NO: Go to Step 4.




STEP 4. Check the combination meter connector C-102 for damage.

Q: Is combination meter connector C-102 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-102 and ground.

Q: Is the harness wires between combination meter connector C-102 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-102.
1. Disconnect the combination meter connector C-102.
2. Start the engine and run at idle.
3. Measure the voltage between terminal 33 and ground.

Q: Is the voltage approximately 10 volts?

YES: Repair or repair the combination meter (printed-circuit board or speedometer and tachometer).
NO: Go to Step 7.













STEP 7. Check the ignition failure sensor connector B-03 <2.4L engine>, distributor assembly connector B-22 <3.0L engine>, automatic compressor controller connector C-15 <3.0L engine> and combination meter connector C-102 for damage.

Q: Are ignition failure sensor connector B-03 <2.4L engine>, distributor assembly connector B-22 <3.0L engine>, automatic compressor controller connector C-15 <3.0L engine> and combination meter connector C-102 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-102 to ignition failure sensor connector B-03 <2.4L engine>, distributor assembly connector B-22 <3.0L engine> and automatic compressor controller connector C-15 <3.0L engine>.

NOTE: After checking intermediate connector C-25, check the wires. If intermediate connector C-25 is damaged, repair or replace it. Refer to Harness Connector Inspection.

Q: Are the harness wires from combination meter connector C-102 to ignition failure sensor connector B03 <2.4L engine>, distributor assembly connector B-22 <3.0L engine> and automatic compressor controller connector C-15 <3.0L engine> in good condition?

YES: There is no action to be taken.
NO: Repair it. The tachometer should work normally.