DTC C0665: Chassis Pitch Signal Circuit

The RTD module receives a chassis pitch signal from Powertrain Control Module (PCM) on the chassis pitch angle signal circuit. Under normal conditions, signal is 4.5-5.5 volt reference. PCM grounds the chassis pitch signal circuit when vehicle accelerates rapidly or brakes hard. When ignition is turned to RUN and RTD module does not detect a low to high transition on chassis pitch signal from PCM, DTC C0665 will set and store in RTD memory. At that time, RTD ignores chassis pitch angle and a SERVICE RIDE CONTROL message is sent to IPC.

1. Perform RTD diagnostic system check. See RTD DIAGNOSTIC SYSTEM CHECK  under DIAGNOSIS & TESTING. After performing RTD diagnostic system check, go to next step.
2. Connect scan tool. Turn ignition on. Using scan tool, observe Chassis Pitch Angle parameter in RTD data list. If scan tool display is INACTIVE, go to step  4 . If display is not INACTIVE, go to next step.
3. Turn ignition off. Disconnect PCM. Turn ignition on. Using scan tool, observe Chassis Pitch Angle parameter. If scan tool displays INACTIVE, go to step  8 . If display is not INACTIVE, go to step  6 .
4. Turn ignition off. Disconnect PCM connectors. Connect 3-amp fused jumper wire between terminal No. 38 (Pink/White wire) at PCM connector and ground. See Figure . Turn ignition on. Using scan tool, observe Chassis Pitch Angle data parameter. If scan displays ACTIVE, go to step  8 . If display is not INACTIVE, go to next step.
5. Check Pink/White wire for an open or short to voltage. If an open or short to voltage is present, repair and go to step  11 . If open or short is not present, go to step  7 .
6. Check Pink/White wire for short to ground. If short to ground is present, repair and go to step  11 . If short is not present, go to next step.
7. Check for poor connections at harness connector of RTD module. If poor connection is present, repair and go to step  11 . If poor connections are not present, go to step  9 .
8. Check for poor connections at harness connector of PCM module. If poor connection is present, repair and go to step  11 . If poor connections are not present, go to step  10 .
9. Replace RTD control module. See RTD CONTROL MODULE  under REMOVAL & INSTALLATION. After repairs, go to step  11 .
10. Replace PCM. Go to step  11 .
11. Turn ignition off. Connect or install any connector or components that were disconnected or removed. Turn ignition on. Using scan tool, clear all DTCs. Operate vehicle. Repeat self test. If DTCs reset, go to step  2 . If DTCs do not reset, system is okay.