Pinpoint Test B: DTC B1627 - PRNDL Reverse Input Circuit Failure

WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Parking Aid for schematic and connector information.

Normal Operation

With the ignition switch in the RUN position, and the gear selector in REVERSE (R), the parking aid system calculates the distance to an object by the use of a radar sensor. Reverse status is communicated to the parking aid module (PAM) from the digital transmission range (TR) sensor on circuit 140 (BK/PK).

DTC B1627 (PRNDL Reverse Input Circuit Failure) - is a continuous and on-demand DTC that sets if the PAM detects a short to voltage on the PRNDL reverse input circuit 140 (BK/PK).

This pinpoint test is intended to diagnose the following:

Wiring, terminals or connectors
Parking aid system inline harness
Digital TR sensor
PAM

PINPOINT TEST B: DTC B1627 - PRNDL REVERSE INPUT CIRCUIT FAILURE

CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Diagnostic measurements are made at the parking aid system inline harness connector located in the luggage compartment, forward of the LH tail light assembly.

B1 CHECK CIRCUIT 140 (BK/PK) FOR A SHORT TO VOLTAGE
- Key in OFF position.
- Disconnect: Parking Aid System Inline Harness C406
- Key in ON position.
- Measure the voltage between the parking aid system inline harness C406-6 circuit 140 (BK/PK), body harness side and ground.
- Is any voltage indicated?
1. YES : Go to B2.
2. NO : Go to B3.
B2 CHECK DIGITAL TR SENSOR FOR A SHORT TO VOLTAGE
- Key in OFF position.
- Disconnect: Digital TR Sensor C167
- Key in ON position.
- Measure the voltage between the parking aid system inline harness C406-6 circuit 140 (BK/PK), body harness side and ground.
- Is any voltage indicated?
1. YES : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
2. NO : INSTALL a new digital TR sensor. REFER to IN-VEHICLE SERVICING article.
B3 CHECK THE PARKING AID SYSTEM INLINE HARNESS
- Inspect the parking aid system inline harness for an open, short to voltage, or a short to ground.
- Is the parking aid system inline harness OK?
1. YES : Go to B4.
2. NO : INSTALL a new or REPAIR the parking aid system inline harness. CLEAR the DTCs. REPEAT the self-test.
B4 CHECK FOR CORRECT PAM OPERATION
- Disconnect the PAM connector.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect the PAM connector and make sure it seats correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
1. YES : INSTALL a new PAM. REFER to Parking Aid Module (PAM) . TEST the system for normal operation.
2. 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.