Additional Reference Information
Speed Control Servo Operation and FunctionNOTE
ALL FUNCTIONALITY LISTED BELOW IS PERFORMED WITH CONNECTORS CONNECTED AND KEY IN RUN POSITION UNLESS OTHERWISE NOTED.
PIN 1 - SCP+ Standard Corporate Protocol Bus. Receives vehicle speed, BOO/BPP, throttle position and gear selector position information. It outputs:
cluster telltale signal, speed control button status and DTCs. To confirm operation, use a DST to retrieve any diagnostic trouble codes using the on demand self test then confirm steering wheel button operation by pressing each button and observe that the appropriate PID changes.
PIN 2 - SCP- Standard Corporate Protocol Bus. Receives vehicle speed, BOO/BPP, throttle position and gear selector position information. It outputs:
cluster telltale signal, speed control button status and DTCs. To confirm operation, use a DST to retrieve any diagnostic trouble codes using the on demand self test then confirm steering wheel button operation by pressing each button and observe that the appropriate PID changes.
PIN 3 - Not Used. PIN 4 - Not Used.
PIN 5 - Control Switch Input. (Note: Performed with key in OFF position) Remove connector C122, using a DVOM set to resistance, measure the resistance between Pins 5 and 6. See table of resistance readings below for each switch when it is depressed.
PIN 6 - Control Switch Return. This is the return side of the switches, which are grounded internally to the servo to Pin 10. If test for Pin 5 checks good then Pin 6 is functioning normally.
PIN 7 - Power. Remove connector C122, Using a DVOM set to DC volts, measure the voltage between pin 7 and ground. You should read greater than 10 volts with the key in the run position. Record the voltage from pin 7 to ground, then re-measure with a test lamp (1156) from pin 7 to ground, to ensure current carrying capability. The difference between the two measurements should be less than 0.3 VDC. If voltage drop test fails then check wiring.
PIN 8 - Not used.
PIN 9 - Brake Deactivator Switch. This is a redundant shutoff switch. Without depressing the brake pedal, measure voltage on Pin 9, and re-measure with a test lamp (1156) from Pin 9 to ground, to ensure current carrying capability. The difference between the two measurements should be less than 0.3 VDC. The system requires enough current at this pin to engage properly. If voltage drop test fails, check for corroded wiring or deactivation switch. You should measure 0 volts at Pin 6 when the brake pedal is depressed firmly.
An alternate to the voltage drop test would be to disconnect the switch connector and measure the switch resistance. It should be less than 5 ohms. If the switch is suspected, a bypass test may also be done: On the harness side of the BPS connector, connect a jumper between the two deactivation switch pins and drive vehicle above 30 MPH (48 Km/h). If speed control engages then the brake deactivation switch was faulty, otherwise wiring is at fault.
PIN 10 - Ground. Using a DVOM set to DC volts, measure the voltage between B+ and Pin 10. You should read greater than 10 volts. Record the voltage between B+ and Pin 10 , then re-measure with a test lamp (1156) from B+ to pin 10. The difference between the two measurements should be less than 0.3 VDC. If voltage drop test fails then check wiring. This verifies circuit can carry proper load as well as continuity to ground.