Pinpoint Test F: DTC P1561

WARNING: This page is about a different car, the 2009 Ford RV Cutaway, 2009 Ford Econoline, 2009 Ford E450 Super Duty, and 2009 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.

F1 CHECK THE PCM BRAKE ON/OFF (BOO1) PID
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger - PCM.
- Monitor the BOO1 PID while pressing and releasing the brake pedal.
- Does the PID agree with the pedal position?
- Yes: Go to F2 .
- No: REFER to EXTERIOR LIGHTING to continue diagnosis of the stoplamps.
F2 CHECK THE TRANSDUCER CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: PCM C175B (gasoline engines).
- Disconnect: PCM C1551B (diesel engines).
- Disconnect: PCM C1551E (diesel engines).
- Disconnect: Brake Pressure Transducer C1025 (all engines).
- Ignition ON.
- Measure the voltage between ground and:
  - brake pressure transducer C1025-1, circuit RE407 (YE/VT), harness side.
  - brake pressure transducer C1025-2, circuit LCA16 (GN), harness side.
  - brake pressure transducer C1025-3, circuit RCA16 (BU/BN), harness side.
  Fig 1: Measuring Voltage Between Ground And Brake Pressure Transducer C1025-1, Circuit RE407 (YE/VT), Harness Side
- Is any voltage present?
- Yes: REPAIR the affected circuit(s). CLEAR the DTC. REPEAT the self-test.
- No: Go to F3 .
F3 CHECK THE TRANSDUCER CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between ground and:
  - brake pressure transducer C1025-1, circuit RE407 (YE/VT), harness side.
  - brake pressure transducer C1025-2, circuit LCA16 (GN), harness side.
  - brake pressure transducer C1025-3, circuit RCA16 (BU/BN), harness side.
  Fig 2: Measuring Resistance Between Ground And Brake Pressure Transducer C1025-1, Circuit RE407 (YE/VT), Harness Side
- Are the resistances greater than 10,000 ohms?
- Yes: Go to F4 .
- No: REPAIR the affected circuit(s). CLEAR the DTC. REPEAT the self-test.
F4 CHECK THE TRANSDUCER CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between brake pressure transducer C1025-1, circuit RE407 (YE/VT), harness side and brake pressure transducer C1025-2, circuit LCA16 (GN), harness side.
  
  Fig 3: Measuring Resistance Between Brake Pressure Transducer C1025-1, Circuit RE407 (YE/VT) And Brake Pressure Transducer C1025-2, Circuit LCA16 (GN)
- Measure the resistance between brake pressure transducer C1025-1, circuit RE407 (YE/VT), harness side and brake pressure transducer C1025-3, circuit RCA16 (BU/BN), harness side.
  
  Fig 4: Measuring Resistance Between Brake Pressure Transducer C1025-1, Circuit RE407 (YE/VT) And Brake Pressure Transducer C1025-3, Circuit RCA16 (BU/BN)
- Measure the resistance between brake pressure transducer C1025-2, circuit LCA16 (GN), harness side and brake pressure transducer C1025- 3, circuit RCA16 (BU/BN), harness side.
  
  Fig 5: Measuring Resistance Between Brake Pressure Transducer C1025-2, Circuit LCA16 (GN) And Brake Pressure Transducer C1025- 3, Circuit RCA16 (BU/BN)
- Are the resistances greater than 10,000 ohms?
- Yes: Go to F5 .
- No: REPAIR the affected circuit(s). CLEAR the DTC. REPEAT the self-test.

F5 CHECK THE TRANSDUCER CIRCUITS FOR AN OPEN

For vehicles equipped with a gasoline engine, measure the resistance between PCM C175B, harness side and brake pressure transducer C1025, harness side as indicated in the following chart:

CIRCUIT REFERENCE CHART

PCM	Circuit	Brake Pressure Transducer
C175B-58	RE407 (YE/VT)	C1025-1
C175B-52	RCA16 (BU/BN)	C1025-2
C175B-27	RCA16 (BU/BN)	C1025-3

Fig 6: Measuring Resistance Between PCM C175B, Harness Side And Brake Pressure Transducer C1025, Harness Side

For vehicles equipped with a diesel engine , measure the resistance between PCM C1551B and C1551E, harness side and brake pressure transducer C1025, harness side as indicated in the following chart:

CIRCUIT REFERENCE CHART

PCM	Circuit	Brake Pressure Transducer
C1551B-41	RE407 (YE/VT)	C1025-1
C1551E-40	RCA16 (BU/BN)	C1025-2
C1551E-28	RCA16 (BU/BN)	C1025-3

Fig 7: Measuring Resistance Between PCM C1551B And C1551E, Harness Side And Brake Pressure Transducer C1025, Harness Side

Are the resistances less than 5 ohms?

Yes: Go to F6 .
No: REPAIR the affected circuit(s). CLEAR the DTC. REPEAT the self-test.

F6 CHECK THE PCM 5 VOLT OUTPUT
- Connect: PCM C175B (gasoline engines).
- Connect: PCM C1551B (diesel engines).
- Connect: PCM C1551E (diesel engines).
- Ignition ON.
- Measure the voltage between brake pressure transducer C1025-2, circuit LCA16 (GN), harness side and ground
  
  Fig 8: Measuring Voltage Between Brake Pressure Transducer C1025-2, Circuit LCA16 (GN), Harness Side And Ground
- Is the voltage approximately 5 volts?
- Yes: INSTALL a new brake pressure transducer. Make sure to LUBRICATE the O-ring seal with clean, specified brake fluid before installation. CLEAR the DTCs. REPEAT the self-test.
- No: Go to F7 .
F7 CHECK FOR CORRECT PCM OPERATION
- Disconnect: All PCM Connectors.
- Check the PCM connectors and the brake fluid pressure transducer connector for:
  - corrosion.
  - spread terminals.
  - pushed-out pins.
- Connect: All PCM Connectors.
- Connect: Brake Fluid Pressure Transducer C1025.
- Make sure the connectors seat properly, then operate the system and verify the concern is still present.
- Is the concern still present?
- Yes: INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS - GASOLINE ENGINES for gasoline engine vehicles and ELECTRONIC ENGINE CONTROLS - DIESEL ENGINE for diesel engine vehicles. CLEAR the DTCs. REPEAT the self-test.
- No: The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. CARRY OUT the self-test with the brake pedal not applied.