Normal Operation
The voltage required for correct Electronic Power Assist Steering (EPAS) system operation is 9-16 volts. Above or below that voltage range, DTC B1317 (battery voltage high) or DTC B1318 (battery voltage low) will be set.
Fused ignition voltage for the EPAS system is supplied to the control module 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 Power Steering Control Module (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).
- DTC B1317 (Battery Voltage High) - When the battery or charging system voltage exceeds 16 volts for more than 1000 ms, DTC B1317 will be set.
- DTC B1318 (Battery Voltage Low) - When the battery or charging system voltage drops below 9 volts for more than 4000 ms, DTC B1318 will be set.
- These DTCs may also result in a reduced amount of steering assist.
This pinpoint test is intended to diagnose the following
- Wiring, terminals or connectors
- Charging system
- PSCM
The voltage required for correct Electronic Power Assist Steering (EPAS) system operation is 10-16 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 Description | Fault Trigger Condition |
|---|---|
| B2277 - Electric Power Steering Motor Malfunction B2278 - Steering Shaft Torque Sensor Malfunction B227B - Steering Shaft Position Sensor Malfunction | An open or short in the Power Steering Control Module (PSCM) power or ground 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 CHART
This pinpoint test is intended to diagnose the following
- Wiring, terminals or connectors
- PSCM
With a fully charged battery and the ignition in the ON position, the Electronic Power Assist Steering (EPAS) system should provide adequate assist to maneuver the vehicle and should be able to return to the straight-ahead position with little difficulty. The assist provided by the EPAS system should be smooth and consistent at all times. The steering and suspension components should be free of any binding conditions and should not interfere with the steering assist provided by the EPAS system.
Fused ignition voltage for the EPAS system is supplied to the control module by Smart Junction Box (SJB) fuse 35 (10A) along circuit CBP35 (YE/GY). Fused battery voltage for the EPAS system motor is supplied to the power steering control module by Battery Junction Box (BJB) 80A MIDI (WH) fuse along circuit SBB01 (RD). Ground for the power steering control module is provided along circuit GD116 (BK/VT). The power steering control module communicates with the other vehicle control modules along the High Speed Controller Area Network (HS-CAN) bus, circuits VDB04 (WH/BU) and VDB05 (WH).
This pinpoint test is intended to diagnose the following
- Steering wheel position sensor calibration
- Steering components
- Suspension components
- Fuse(s)
- Wiring, terminals or connectors
- Steering column
See also:
• SUPPLEMENTAL RESTRAINT SYSTEM