Procedure 2 - Tachometer Inoperative

Tachometer Circuit:

Connectors:

CIRCUIT OPERATION
- The tachometer power is supplied from the ignition switch (IG1) 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 wire or connector

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 MB991502.

STEP 1. Is MFI system DTC P0300 output?
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.
If DTC P0300 is not displayed, go to Step 2.
If DTC P0300 is displayed, refer to Diagnosis (Computers/Testing).

STEP 2. Check the speedometer operation.
If the speedometer works normally, refer to Inspection Procedure 1.
If the speedometer does not work normally, go to Step 3.

STEP 3. Check the combination meter (tachometer) ground circuit at the combination meter connector C-42.
1. Disconnect the combination meter connector C-42 and measure at the harness side.
2. Resistance between terminal 27 and ground.
- Should be less than 2 Ohms.
If open circuit, go to Step 4.
If less than 2 Ohms, go to Step 6.

STEP 4. Check the combination meter connector C-42 for damage.
If the combination meter connector C-42 is damaged, repair or replace it. Refer to Harness Connector Inspection.
The tachometer should work normally.
If the connector is in good condition, go to Step 5.

STEP 5. Check the harness wire between combination meter connector C-42 and ground.
If the harness wire between combination meter connector C-42 and ground is damaged, repair it.
The tachometer should work normally.

STEP 6. Check the ignition signal input circuit at the combination meter connector C-42.
1. Disconnect the combination meter connector C-42 and measure at the harness side.
2. Start the engine and run at idle.
3. Voltage between terminal 33 and ground.
- Voltage should be approximately 10 volts.
If not approximately 10 volts, go to Step 7.
If approximately 10 volts, repair or replace the combination meter (printed-circuit board or speedometer and tachometer). The tachometer should work normally.

2.4L Engine:

3.0L Engine:

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-13 <3.0L engine> and combination meter connector C-42 for damage.
If the ignition failure sensor connector B-03 <2.4L engine>, distributor assembly connector B-22 <3.0L engine>, automatic compressor controller connector C-13 <3.0L engine> and combination meter connector C-42 are damaged, repair or replace them. Refer to Harness Connector Inspection.
The tachometer should work normally.
If the connectors are in good condition, go to Step 8.

2.4L Engine:

3.0L Engine:

STEP 8. Check the harness wires from combination meter connector C-42 to ignition failure sensor connector B-03 <2.4L engine>, distributor assembly connector B-22 <3.0L engine> and automatic compressor controller connector C-13 <3.0L engine>.

NOTE: After checking intermediate connector C-28, check the wires. If intermediate connector C-28 is damaged, repair or replace it. Refer to Harness Connector Inspection.

If the harness wires from combination meter connector C-42 to ignition failure sensor connector B-03 <2.4L engine>, distributor assembly connector B-22 <3.0L engine> and automatic compressor controller connector C-13 <3.0L engine> is damaged, repair or replace them.
The tachometer should work normally.