Pinpoint Test D: Reversing Lamp Switch
- Refer to ELECTRONIC ENGINE CONTROLS - 5.0L
for schematic and connector information.
Normal Operation and Fault Conditions
The reversing lamp switch is a normally open switch located on the LH side of the transmission case. When the transmission is placed in reverse, the reversing lamp switch pin is pressed, completing the circuit. The PCM monitors the reversing lamp switch circuit to detect when reverse is selected. This data is used for several vehicle features and functions including reverse camera activation, reverse parking aid, cross traffic alert, and reverse lamps.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition PCM P0812:00 Reverse Input Circuit: No Sub Type Information This DTC sets when the PCM detects and open or shorted reversing lamp switch circuit. Possible Sources
- Reversing lamp switch
- Wiring, terminals or connectors
- PCM fault
- D1 CHECK THE OPERATION OF THE REVERSING LAMP SWITCH
- Start engine and allow to idle.
- Engage parking brake.
- Press and hold the clutch pedal for the duration of this test.
- Access the PCM and monitor the REV_SWPID
- Move the gearshift lever between neutral and reverse several times while observing PID REV_SW.
Does PID REV_SW change appropriately as the gearshift lever is moved between neutral and reverse?
Yes A reversing lamp switch concern is not present at this time. No If the PID always indicates the transmission is in reverse, GO to D2 If the PID never indicates the transmission is in reverse, GO to D4 - D2 CHECK FOR A SHORTED REVERSING LAMP SWITCH
- Ignition OFF.
- Disconnect Reversing lamps switch C169 .
- Ignition ON.
- Access the PCM and monitor the REV_SWPID
Does the PID indicate the transmission is in reverse?
Yes GO to D3 No INSTALL a new reversing lamp switch. REFER to: Reversing Lamp Switch - D3 CHECK THE REVERSE SWITCH CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect PCM C175B .
- Measure:
Positive Lead Measurement / Action Negative Lead C175B-6 Ground
Is the resistance greater than 10, 000 ohms?
Yes GO to D7 No REPAIR the short to ground. - D4 BYPASS THE REVERSING LAMP SWITCH
- Ignition OFF.
- Disconnect Reversing lamps switch C169 .
- Ignition ON.
- Access the PCM and monitor the REV_SWPID
Does the PID indicate the transmission is in reverse?
Yes INSTALL a new reversing lamp switch. REFER to: Reversing Lamp Switch No GO to D5 - D5 CHECK THE REVERSING LAMP SWITCH CIRCUIT FOR AN OPEN
- Ignition OFF.
- Remove the fused jumper.
- Disconnect PCM C175B .
Is the resistance less than 3 ohms?
Yes GO to D6 No REPAIR the open circuit. - D6 CHECK THE SIGNAL RETURN CIRCUIT FOR AN OPEN
Is the resistance less than 3 ohms?
Yes GO to D7 No REPAIR the open circuit. - D7 CHECK FOR CORRECT PCM (POWERTRAIN CONTROL MODULE) OPERATION
- Ignition OFF.
- Disconnect and inspect the PCM connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Reconnect the PCM and all other previously disconnected connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new PCM. Refer to the appropriate Removal and Installation procedure in the appropriate Electronic Engine Controls service information . No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.