Pinpoint Test O: The STOPLAMPS Are On Continuously

WARNING: This page is about a different car, the 2004 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.

O1 DETERMINE THE ALWAYS ON STOPLAMPS
- Observe the stoplamps.
- Are all the stoplamps illuminated?
1. Yes : GO to O3.
2. No : GO to O2.
O2 CHECK THE CONTROL GROUND CIRCUIT FOR SHORT TO GROUND
- Key in OFF position.
- Disconnect: REM C420e.
- Does the lamp continue to illuminate?
1. Yes : For the high mounted stoplamp, REPAIR circuit 31S -LG6 (BK/YE) or 31S-LG6A (BK/YE) as necessary. TEST the system for normal operation.
  For the LH stoplamp, REPAIR circuit 31S-LG14 (BK/OG). TEST the system for normal operation.
  
  For the RH stoplamp, REPAIR circuit 31S-LG21 (BK/GN) or31S-LG14 (BK/OG) as necessary. TEST the system for normal operation.
2. No : GO to O10.
O3 CHECK THE BPP SWITCH
- Key in OFF position.
- Disconnect: BPP Switch C278.
- Do the stoplamps continue to illuminate?
1. Yes : If equipped with IVD, GO to O4.
  If not equipped with IVD, GO to O6.
2. No : INSTALL a new BPP switch. REFER to BRAKE PEDAL POSITION (BPP) SWITCH . CLEAR the DTCs. TEST the system for normal operation.
O4 CHECK THE IVD MODULE
- Disconnect: IVD Module C155.
- Do the stoplamps continue to illuminate?
1. Yes : GO to O6.
2. No : GO to O5.
O5 CHECK CIRCUIT 29S-CF1 (OG/YE) FOR SHORT TO POWER
- Measure the voltage between the BPP switch C278-2, circuit 29S-CF1 (OG/YE), harness side and ground.
  
  Fig 1: Measuring Voltage Between BPP Switch C278-2, Circuit 29S-CF1 (OG/YE), Harness Side And Ground
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
1. Yes : REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
2. No : GO to O11.
O6 CHECK THE ABS MODULE
- Disconnect: ABS Module C135.
- Do the stoplamps continue to illuminate?
1. Yes : GO to O7.
2. No : GO to O12.
O7 CHECK THE ELECTRIC PARKING BRAKE MODULE
- Disconnect: Electric Parking Brake Module C4206.
- Do the stoplamps continue to illuminate?
1. Yes : GO to O8.
2. No : GO to O13.
O8 CHECK THE PCM
- Disconnect: PCM C175a.
- Do the stoplamps continue to illuminate?
1. Yes : GO to O9.
2. No : GO to O14.
O9 CHECK THE REM
- Disconnect: REM C420b.
- Do the stoplamps continue to illuminate?
1. Yes : REPAIR circuit 29S -DK30 (OG), 29S -CF1 (OG/YE), 29S-CF2 (OG/BU), 29S-CF58 (OG/GN) or29S-RE13 (OG) as necessary. CLEAR the DTCs. TEST the system for normal operation.
2. No : GO to O1.
O10 CHECK FOR REM OPERATION
- Key in OFF position.
- Disconnect all REM connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all REM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. Yes : INSTALL a new REM. Refer to MODULE COMMUNICATIONS NETWORK . TEST the system for normal operation.
2. No : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. REPEAT the self-test.
O11 CHECK FOR IVD MODULE OPERATION
- Key in OFF position.
- Disconnect all IVD module connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all IVD module connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. Yes : INSTALL a new ABS module. REFER to ANTI-LOCK CONTROL . TEST the system for normal operation.
2. No : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. REPEAT the self-test.
O12 CHECK FOR ABS MODULE OPERATION
- Key in OFF position.
- Disconnect all ABS module connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all ABS module connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. Yes : INSTALL a new ABS module. REFER to ANTI-LOCK CONTROL . TEST the system for normal operation.
2. No : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. REPEAT the self-test.
O13 CHECK FOR ELECTRIC PARKING BRAKE MODULE OPERATION
- Key in OFF position.
- Disconnect all electric parking brake module connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all electric parking brake module connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. Yes : INSTALL a new electric parking brake module. REFER to BRAKE SYSTEM TEST the system for normal operation.
2. No : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. REPEAT the self-test.
O14 CHECK FOR PCM OPERATION
- Key in OFF position.
- Disconnect all PCM connectors.
- Check for:
  - corrosion
  - pushed-out pins
- Connect all PCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. Yes : INSTALL a new PCM. Refer to INTAKE AIR, FUEL CHARGING, STARTING & ENGINE ELECTRONICS - 3.0L (4V) - LS or INTAKE AIR, FUEL CHARGING, STARTING & ENGINE ELECTRONICS - 3.9L - LS . TEST the system for normal operation.
2. No : The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. REPEAT the self-test.