Engine Mount Control System: Troubleshooting: A/T:

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.
Before performing engine mount control system troubleshooting, check for damage to the suspension, subframe, body, or exhaust.

Follow this procedure if the engine vibrates excessively when idling.

Warm up the engine to normal operating temperature (the cooling fan comes on twice).
Is the idle speed less than 750 rpm?
1. YES -Go to step 2.
2. NO -Adjust the idle speed (see IDLE SPEED & MIXTURE ).
Fully depress the brake pedal.
With the transmission in gear, have an assistant disconnect and reconnect the engine mount control solenoid valve 2P connector from the engine mount control solenoid valve.
Is there a noticeable change in idle smoothness when the engine mount control solenoid valve 2P connector is disconnected?
1. YES -Reconnect the engine mount control solenoid valve 2P connector to the solenoid valve. The engine mount control system is OK.
2. NO -Go to step 4.
Shift to Park or Neutral position.
Disconnect the engine mount control solenoid valve 2P connector from the engine mount control solenoid valve.
Measure voltage between the No.2 terminal and body ground.

Fig 1: Measuring Voltage Between The No.2 Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES -Go to step 7.
2. NO -Repair open in the wire between engine mount control solenoid valve and No.6 (15A) fuse in the driver's under-dash fuse/relay box.
Measure voltage between the No.1 terminal and No.2 terminal.

Fig 2: Measuring Voltage Between The No.1 Terminal And No.2 Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES -Go to step 8.
2. NO -Repair open in the wire between powertrain control module (PCM) (A2) and the engine mount control solenoid valve 2P connector. If the wire is OK, substitute a known-good PCM and recheck.
Raise the engine speed above 1,000 rpm.
Measure voltage between the engine mount control solenoid valve 2P connector No.1 terminal and No.2 terminal.

Fig 3: Measuring Voltage Between The Engine Mount Control Solenoid Valve 2P Connector No.1 Terminal And No.2 Terminal
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES -Repair short to body ground in the wire between PCM (A2) and the engine mount control solenoid valve. If the wire is OK, substitute a known-good PCM and recheck.
2. NO -Go to step 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.

Fig 4: Disconnecting The Upper Vacuum Hose From The Engine Mount Control Solenoid Valve
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Does the engine mount hold vacuum?
1. YES -Go to step 11.
2. NO -Either the vacuum hose or one of the engine mounts has a vacuum leak. Repair as needed.
Release the vacuum, then apply vacuum again.
Is there a noticeable change in idle smoothness with and without vacuum applied?
1. YES -Go to step 12.
2. NO -Replace the front engine mount and/or rear engine mount.
Disconnect the upper vacuum hose (A) from the engine mount control solenoid valve (B) and connect a vacuum pump/gauge to a hose connected to the engine mount control solenoid valve.

Fig 5: Disconnecting The Upper Vacuum Hose From The Engine Mount Control Solenoid Valve
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there manifold vacuum at idle, and a decrease in manifold vacuum when you raise the engine speed above 1,000 rpm?
1. YES -Replace the engine mount control solenoid valve.
2. NO -A hose is restricted or pinched or the intake manifold port is plugged.