Cruise Control Communication Circuit Troubleshooting

A/T 

1. Start the engine.
2. Turn on the cruise control main switch, then drive the vehicle at speeds over 25 mph (40 km/h) with the cruise control set.

   Does the cruise control operate? 

   1. YES -  Go to step 3.
   2. NO -  Check the cruise control actuator (see CRUISE CONTROL ACTUATOR INPUT TEST  ).
3. Turn the ignition switch OFF.
4. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC) (see step 2 on HOW TO USE THE HDS (HONDA DIAGNOSTIC SYSTEM) ). Turn the ignition switch ON (II), and jump the SCS line with the HDS, then turn the ignition switch OFF.
   NOTE: This step must be done to protect the powertrain control module (PCM) from damage.
5. Disconnect PCM connector D (17P) and cruise control actuator 12P connector.
6. Check for continuity between PCM connector terminal D12 and body ground.
   Fig 1: Checking Continuity Between PCM Connector Terminal And Body Ground

   Courtesy of AMERICAN HONDA MOTOR CO., INC.

   Is there continuity? 

   1. YES -  Repair a short to ground in the wire between PCM connector terminal D12 and the cruise control actuator 12P connector terminal No. 10.
   2. NO -  Go to step 7.
7. Check for continuity between PCM connector terminal D12 and cruise control actuator 12P connector terminal No. 10.
   Fig 2: Checking Continuity Between PCM Connector Terminal And Cruise Control Actuator Connector Terminal

   Courtesy of AMERICAN HONDA MOTOR CO., INC.

   Is there continuity? 

   1. YES -  Go to step 8.
   2. NO -  Repair an open in the wire between PCM connector terminal D12 and cruise control actuator 12P connector terminal No. 10.
8. Reconnect the PCM connector D (17P) and the cruise control actuator 12P connector.
9. Disconnect the HDS.
10. Connect a voltmeter between PCM connector terminal D12 and body ground. Drive the vehicle at speeds over 25 mph (40 km/h) with the cruise control set, and watch the voltmeter.
    Fig 3: Connecting Voltmeter Between PCM Connector Terminal And Body Ground

    Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there about 1 V? 

    1. YES -  Update the PCM if it does not have the latest software (see ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING ) or substitute a known-good PCM (see HOW TO SUBSTITUTE THE ECM/PCM ), then recheck. If the system works properly, and the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see ECM/PCM REPLACEMENT ).
    2. NO -  Substitute a known-good cruise control actuator, then recheck. If the system works properly, replace the original cruise control actuator (see CRUISE CONTROL ACTUATOR/CABLE REPLACEMENT  ).