The BCP sensor is supplied with a 5 V reference signal at Pin 2 through the valve cover gasket Pin B from
ECM Pin X1–14. The BCP sensor is supplied a signal ground at Pin 1 through the valve cover gasket Pin C from ECM Pin X1–6. The BCP sensor sends a signal from sensor Pin 3 through valve cover gasket Pin A to ECM Pin X2–11.
Fault Detection / Management
The ECM continuously monitors the signal of the BCP sensor to determine if the signal is within an expected
range. If the ECM detects a voltage greater or less than expected, the ECM will set a DTC and illuminate the amber ENGINE lamp.
BCP Diagnostic Trouble Codes (DTCs)
DTCs are read using the EST or by counting the flashes from the amber and red ENGINE lamps.
DTC 126
BCP signal out-of-range low
• DTC 126 is set by the ECM if signal voltage is less than 0.039 V for more than 0.35 second.
• DTC 126 can be set due to an open or short to ground on the signal circuit, a failed BCP sensor, an open VREF circuit or VREF short to ground.
• When DTC 126 is active the amber ENGINE lamp is illuminated.
DTC 127
BCP signal out-of-range high
• DTC 127 is set by the ECM if the signal voltage is greater than 4.9 V for more than 0.35 second.
• DTC 127 can be set due to a signal circuit shorted to VREF or B+, or a failed BCP sensor.
• When DTC 127 is active the amber ENGINE lamp is illuminated.
DTC 546
Engine brake control pressure below expected range
• DTC 546 is set by the ECM when the brake control pressure is less than injection control pressure by 4 MPa (580 psi) for more than 3.0 seconds.
• DTC 546 can be set due to a bias low BCP sensor or a failed BCP sensor.
• DTC 546 can be set due to an open control circuit (power or ground), a failed brake shut-off valve, or a failed brake shut-off valve solenoid. See “Brake Shut-off Valve – Section 7.
• When DTC 546 is active the amber ENGINE lamp is illuminated.
DTC 547
Engine brake control pressure above expected range
• DTC 547 is set by the ECM when the brake control pressure is greater than desired brake control pressure of 4.5 MPa (653 psi) for more than three seconds.
• DTC 547 can be set due to an open signal ground, VREF shorted to a voltage source higher than 5.5 V, or a faulty BCP sensor.
• DTC 547 can be set due to a control circuit short to B+ or a brake shut-off valve stuck open. See “Brake Shut-off Valve – Section 7.
• When DTC 547 is active the amber ENGINE lamp is illuminated.
Tools
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
• 3-Banana Plug Harness
• 500 Ohm Resistor Harness
• VC Gasket Breakout Harness
• UVC Pressure Breakout Harness
• Breakout Box
• Terminal Test Adapter Kit
