Engine Mount: Testing and Inspection

Troubleshooting

Special Tools Required
Vacuum Pump/Gauge, 0 - 30 in.Hg
A973X-041-XXXXX

NOTE: Check the vacuum hoses and lines for damage and proper connections before troubleshooting.

Follow this procedure if the engine vibrates excessively when idling.

1. Warm up the engine to normal operating temperature (the cooling fan comes on 2 times).

Is the idle speed less than 800 rpm?

YES - Go to step 2.

NO - Adjust the idle speed

2. Fully depress the brake pedal.
3. With the transmission in gear, have an assistant disconnect and reconnect the 2P connector from the engine mount control solenoid valve.

Is there a noticeable change in idle smoothness when the 2P connector is disconnected?

YES - Reconnect the 2P connector to the solenoid valve. The engine mount control system is OK.

NO - Go to step 4.

4. Shift to [N] or [P] position.
5. Disconnect the 2P connector from the engine mount control solenoid valve.




6. Measure voltage between the No.2 terminal and body ground.

Is there battery voltage?

YES - Go to step 7.

NO - Repair open in BLK/YEL wire between the 2P connector and No.6 (15 A) fuse in the driver's under-dash fuse/relay box.




7. Measure voltage between the No.1 and No.2 terminals.

Is there battery voltage?

YES - Go to step 8.

NO - Repair open in GRN/WHT wire between Powertrain Control Module (PCM) (A2) and the 2P connector. If the wire is OK, substitute a known-good PCM and recheck.

8. Raise the engine speed above 1,000 rpm.




9. Measure voltage between the No.1 and No.2 terminals.

Is there battery voltage?

YES - Repair short to body ground in GRN/WHT wire between PCM (A2) and the 2P connector. If the wire is OK, substitute a known-good PCM and recheck.

NO - Go to step 10.




10. Disconnect the upper vacuum hose (A) from the engine mount control solenoid valve (B), and connect a vacuum pump/gauge to the hose. Apply vacuum for 20 seconds.

Does the engine mount hold vacuum?

YES - Go to step 11.

NO - Either the vacuum hose or one of the engine mounts has a vacuum leak. Repair as needed.

11. Release the vacuum, then apply vacuum again.

Is there a noticeable change in idle smoothness with and without vacuum applied?

YES - Go to step 12.

NO - Isolate and replace the leaking engine mount.




12. Disconnect the lower vacuum hose (A) from the engine mount control solenoid valve (B) and connect a vacuum pump/gauge to the hose.

Is there manifold vacuum at idle a decrease, when you raise the engine speed above 1,000 rpm?

YES - Replace the engine mount control solenoid valve.

NO - A hose is restricted or pinched or the intake manifold port is plugged, Repair as needed.