Engine Mount: Testing and Inspection
Engine Mount Control System Troubleshooting
Special Tools Required
- Vacuum pump/gauge, 0-30 in Hg Snap-on YA4000A or equivalent, commercially available
NOTE: Check the vacuum hoses and the lines for damage and proper connections before troubleshooting.
Follow this procedure if the engine vibrates excessively when idling.
1. Check the idle speed. Testing and Inspection
2. Raise the engine speed from idling to 2,000 rpm.
3. Check the MOUNT CTRL SOL in the PGM-FI DATA LIST with the Honda Diagnostic System (HDS).
Is ON indicated at idling and OFF indicated at 2,000 rpm?
YES - Go to step 4.
NO - Update the engine control module (ECM)/ powertrain control module (PCM) if it does not have the latest software, ECM/PCM Update or substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview then recheck. If the engine mount control system works properly, and the ECM/PCM was updated, the troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. ECM/PCM Replacement (A/T)
4. Turn the ignition switch to LOCK (0).
5. Disconnect the engine mount control solenoid valve 2P connector from the engine mount control solenoid valve.
6. Turn the ignition switch to ON (II).
7. Measure the voltage between engine mount control solenoid valve 2P connector terminal No. 2 and body ground.
Is there battery voltage?
YES - Go to step 8.
NO - Repair open in the wire between engine mount control solenoid valve 2P connector terminal No. 2 and the No. 7 (15 A) fuse in the driver's under-dash fuse/relay box.
8. Start the engine, and let it idle.
9. Measure the voltage between engine mount control solenoid valve 2P connector terminals No. 1 and No. 2 with the engine at idle.
Is there battery voltage?
YES - Go to step 10.
NO - Repair open in the wire between ECM/PCM connector terminal C40 and engine mount control solenoid valve 2P connector terminal No. 1. If the wire is OK, update the ECM/PCM if it does not have the latest software, ECM/PCM Update or substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview and recheck. If the engine mount control system works properly, and the ECM/PCM was updated, the troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. ECM/PCM Replacement (A/T)
10. Raise the engine speed above 2,000 rpm.
11. Measure the voltage between engine mount control solenoid valve 2P connector terminals No. 1 and No. 2.
Is there battery voltage?
YES - Repair short to ground in the wire between ECM/PCM connector terminal C40 and engine mount control solenoid valve 2P connector terminal No. 1. If the wire is OK, update the ECM/PCM if it does not have the latest software, ECM/PCM Update or substitute a known-good ECM/PCM, Initial Inspection and Diagnostic Overview and recheck. If the engine mount control system works properly, and the ECM/PCM was updated, the troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. ECM/PCM Replacement (A/T)
NO - Go to step 12.
12. Turn the ignition switch to LOCK (0).
13. Disconnect the upper vacuum hose (A) from the engine mount control solenoid valve (B), and connect a vacuum pump/gauge, 0-30 in Hg, to the hose. Apply about 20 in Hg of vacuum, and wait 20 seconds.
Does the engine mount hold vacuum?
YES - Go to step 14.
NO - Either the vacuum hose or the engine mount has a vacuum leak. Repair as needed.
14. Release the vacuum, then apply vacuum again.
Is there a noticeable change in idle smoothness with and without vacuum applied?
YES - Go to step 15.
NO - Replace the front engine mount.
15. Connect a vacuum pump/gauge, 0-30 in Hg, to the engine mount control solenoid valve (A).
Is there manifold vacuum at idle, and a decrease in manifold vacuum when you raise the engine speed above 2,000 rpm?
YES - The system is OK.
NO - Replace the engine mount control solenoid valve.
