Inspection Procedure 3

INSPECTION PROCEDURE 3: Tachometer does not Work.

Tachometer Circuit Part 1:

Tachometer Circuit Part 2:

CIRCUIT OPERATION
- The tachometer power is supplied from the ignition switch (IG) circuit.
- The tachometer calculates the engine revolution (r/min) according to the ECM or PCM signals to operate the needle.

TECHNICAL DESCRIPTION (COMMENT)
The cause is thought to be because ECM or PCM signals are not transmitted or due to combination meter error.

TROUBLESHOOTING HINTS
- Malfunction of the combination meter (printed circuit board or speedometer and tachometer)
- Malfunction of the ECM or PCM
- Damaged wiring harness or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991911: MUT-III Main Harness B (Vehicles without CAN communication system)

STEP 1. Check with other meter.

Check to see that the speedometer, fuel gauge and water thermometer operate normally.

Q: Do all other meters operate?

YES . : Go to Step 2.

NO . : Refer to INSPECTION PROCEDURE 5.

STEP 2. Using scan tool MB991958, read the diagnostic trouble code.

CAUTION: To prevent damage to scan tool MB991502 or MB991958, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool.

1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Read the MFI system diagnostic trouble code.

Q: Is DTC output to the MFI system?

YES: Refer to Multiport Fuel Injection (MFI) Diagnosis <2.0L> or Multiport Fuel Injection (MFI) Diagnosis <2.4L> in Computers and Control Systems.

NO: Go to Step 3.

STEP 3. Check combination meter connector C-01 and ECM connector C-117 <2.0L-M/T>, C-137 <2.4L-M/T> or PCM connector C-118 <2.4L-A/T>, C-138 <2.4L-A/T> for damage.

Q: Are combination meter connector C-01 and ECM connector C-117 <2.0L-M/T>, C-137 <2.4L-M/T> or PCM connector C-118 <2.4L-A/T>, C-138 <2.4L-A/T> in good condition?

YES: Go to Step 4.

NO: Repair or replace the connector. Refer to Harness Connector Inspection. The tachometer should work normally.

STEP 4. Check the wiring harness between combination meter connector C-01 (terminal 11) and ECM connector C-117 <2.0L-M/T> (terminal 58), C-137 <2.4L-M/T> (terminal 87) or PCM connector C-118 <2.0L-A/T> (terminal 43), C-138 <2.4L-A/T> (terminal 87).

Q:Are the wiring harness between combination meter connector C-01 (terminal 11) and ECM connector C-117 <2.0L-M/T> (terminal 58), C-137 <2.4L-M/T> (terminal 87) or PCM connector C-118 <2.0L-A/T> (terminal 43), C-138 <2.4L-A/T> (terminal 87) in good condition?

YES: Go to Step 5.

NO: Repair the wiring harness. The tachometer should work normally.

STEP 5. Replace the combination meter and check.

Q: Does the tachometer operate?

YES: There is no action to be taken.

NO: Replace the ECM or PCM . The tachometer should work normally.