Cruise Control Communication Circuit Troubleshooting: A/T

Start the engine.
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 unit (see CRUISE CONTROL UNIT INPUT TEST ) or cruise control actuator (see CRUISE CONTROL SET/DECEL, RESUME/ACCEL, CANCEL SWITCH TEST/REPLACEMENT ).
Turn the ignition switch OFF.
2005-2006 models: Connect the HDS to the data link connector (DLC) (see step 2 on IF THE MIL (MALFUNCTION INDICATOR LAMP) HAS COME ON ). Select SCS mode using the HDS.
Disconnect PCM connector D (17P) and cruise control unit 14P connector.
Check for continuity between PCM connector terminal D12 and body ground.

Fig 1: Checking For Continuity Between PCM Connector Terminal D12 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 unit 14P connector terminal No. 8.
2. NO - Go to step 7.
Reconnect PCM connector D (17P) and the cruise control unit 14P connector.
Connect a voltmeter between cruise control unit 14P connector terminal No. 8 and body ground. Test-drive the vehicle at speeds over 25 mph (40 km/h) with the cruise control set, and watch the voltmeter.

Fig 2: Connecting Voltmeter Between Cruise Control Unit 14P Connector Terminal No. 8 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 1 V?
1. YES - Go to step 9.
2. NO - Replace the cruise control unit.
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 D12 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 1 V?
1. YES - Check for loose connectors of the BLU/ORN wire between the cruise control unit and the PCM. If the wire is OK, update the PCM if it does not have the latest software (see HOW TO UPDATE THE ECM/PCM ), or substitute a known-good PCM (see HOW TO SUBSTITUTE THE ECM/PCM (2002-2004 MODELS) ), and recheck. If the system works properly, replace the original PCM (see ECM/PCM REPLACEMENT ).
2. NO - Repair an open in the wire between PCM connector terminal D12 and the control unit 14P connector terminal No. 8.