Pinpoint Test B: DTCs B2277, B2278 and B227B
Steering System
Pinpoint Tests
Pinpoint Test B: DTCs B2277, B2278 and B227B
Refer to Wiring Diagram Set 43 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Power Steering Controls for schematic and connector information. Diagrams By Number
Normal Operation
The voltage required for correct Electronic Power Assist Steering (EPAS) system operation is 11-16 volts. The power steering motor, torque sensor and steering shaft/wheel position sensor are all integrated into the Power Steering Control Module (PSCM) and the PSCM is integrated into the steering column. If any new components need to be installed, a new steering column must be installed.
Fused ignition voltage is supplied to the PSCM by Smart Junction Box (SJB) fuse 35 (10A) along circuit CBP35 (YE/GY). Fused battery voltage for the power steering motor is supplied to the PSCM by Battery Junction Box (BJB) 80A MIDI (WH) fuse along circuit SBB01 (RD). Ground for the PSCM is provided along circuit GD116 (BK/VT). The PSCM communicates with the other vehicle control modules along the High Speed Controller Area Network (HS-CAN) bus, circuits VDB04 (WH/BU) and VDB05 (WH).
- DTC B2277 (Electric Power Steering Motor Malfunction) - An open or short in the PSCM power or HS-CAN bus circuits will cause the appropriate DTC to set. Also, an internal failure of the steering shaft torque sensor, shaft position sensor or motor will cause the DTC to set.
- DTC B2278 (Steering Shaft Torque Sensor Malfunction) - An open or short in the PSCM power or HS-CAN bus circuits will cause the appropriate DTC to set. Also, an internal failure of the steering shaft torque sensor, shaft position sensor or motor will cause the DTC to set.
- DTC B227B (Steering Shaft Position Sensor Malfunction) - An open or short in the PSCM power or HS-CAN bus circuits will cause the appropriate DTC to set. Also, an internal failure of the steering shaft torque sensor, shaft position sensor or motor will cause the DTC to set.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- PSCM
PINPOINT TEST B: DTCs B2277, B2278 and B227B
NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
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B1 CHECK THE PSCM DTCs
- Review the DTCs retrieved and recorded during Inspection and Verification.
- Are any PSCM DTCs present?
Yes
For DTCs B2278 and/or B227B, GO to B2.
For DTC B2277, GO to B3.
No
The system it operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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B2 VERIFY STEERING WHEEL POSITION SENSOR CALIBRATION
- Carry out the Steering Wheel Position Sensor Calibration procedure, refer to Principles of Operation. Principles of Operation
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - PSCM.
- Does DTC B2278 or B227B return?
Yes
GO to B6.
No
The system it operating correctly at this time. The concern may have been caused by an incomplete or incorrect sensor calibration. CLEAR the DTCs. REPEAT the self-test.
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B3 CHECK FOR IGNITION VOLTAGE AT THE PSCM
- Ignition OFF.
- Disconnect: PSCM C1463A.
- Ignition ON.
- Measure the voltage between PSCM C1463A-1, circuit CBP35 (YE/GY), harness side and ground.
- Is the voltage greater than 11 volts?
Yes
GO to B4.
No
VERIFY SJB fuse 35 (10A) is OK. If OK, REPAIR circuit CBP35 (YE/GY). If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test. Diagrams By Number
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B4 CHECK FOR BATTERY VOLTAGE AT THE PSCM
- Ignition OFF.
- Disconnect: PSCM C1463B.
- Measure the voltage between PSCM C1463B-1, circuit SBB01 (RD), harness side and ground.
- Is the voltage greater than 11 volts?
Yes
GO to B5.
No
VERIFY BJB 80A MIDI (WH) fuse is OK. If OK, REPAIR circuit SBB01 (RD). If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test. Diagrams By Number
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B5 CHECK THE PSCM GROUND CIRCUIT FOR AN OPEN
- Disconnect: PSCM C1463B.
- Measure the resistance between PSCM C1463B-2, circuit GD116 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to B6.
No
REPAIR circuit GD116 (BK/VT). CLEAR the DTCs. REPEAT the self-test.
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B6 CHECK THE PSCM OPERATION
- Disconnect the PSCM connectors.
- Check the connectors for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Connect the PSCM connectors and make sure that they are seated correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new steering column. REFER to Steering Column. 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. REPEAT the self-test.
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