Notes On INTERMITTENTS

Manipulate related BCM and ECM wiring in each gear range while observing BD41 or EI74 values. If a failure is induced, values will change indicating an open or short to ground. Ensure good terminal connections exist at BCM, ECM and PRND321 switch. If terminal contacts are good and code B127 continues to set, replace BCM.

Fig 1: Code B127 Schematic, PRND321 Sensor (1 Of 2)

Fig 2: Code B127 Flow Chart, PRND321 Sensor (1 Of 2)

NOTE: Do not attempt to diagnose this code unless owner complaint is of "Gear Selector Fault" message on the DIC, a "Boxed" PRND321 display on the IPC, or improper gear selection display.

Fig 3: Code B127 Flow Chart, PRND321 Sensor

5) Checks for short to ground in PRND321 to BCM circuit(s).
6) Checks for open in PRND321 to BCM circuit(s).
7) Circuit shorted to ground will result in a "0" display for the circuit.
8) Checks for open PRND321 sensor ground.
9) Open circuit will result in a "1" display for the circuit.

Fig 4: Code B127 Schematic, PRND321 Sensor (2 Of 2)

Fig 5: Code B127 Flow Chart, PRND321 Sensor (2 Of 2)

Fig 6: Code B127 Flow Chart, PRND321 Sensor (1 Of 2)