Section 01-20B: Restraints, Passive—Supplemental Air Bag System
1993 Mustang Workshop Manual
DIAGNOSIS AND TESTING

Diagnostic Trouble Code 46

 

LH Primary Crash Sensor Not Mounted To Vehicle Properly

 

Normal Operation

The diagnostic monitor measures the resistance between Pin 22 (Circuit 622, T/BK) and Pin 3 (diagnostic monitor reference ground). If the diagnostic monitor measures a difference of more than 2.0 ohms between Pin 22 and Pin 3, it will flash out Diagnostic Trouble Code 46.

Note that Circuit 622 (T/BK) is attached to the side of the LH primary crash sensor case. In addition, the case is grounded to the vehicle.

 

Possible Causes

High resistance on Pin 22 (Circuit 622, T/BK) to ground can be caused by:

  1. A poor connection due to loose mounting, dirt, or corrosion at the LH primary crash sensor mounting location.
  1. An open or damaged wire in Circuit 622 (T/BK) from Pin 22 of the diagnostic monitor harness connector to LH primary crash sensor.
  1. An open circuit inside LH radiator primary crash sensor.


Electrical Schematic—Diagnostic Trouble Code 46




 

DIAGNOSTIC TROUBLE CODE 46

 

46-1 VERIFY CONDITION

Yes
GO to 46-2.

No
Read the normal operation description for this diagnostic trouble code. EXAMINE the diagnostic trouble code schematic and look for areas where intermittent conditions would occur (connectors, splices, crimps, etc.).
DO NOT proceed with Pinpoint Test until the code is flashing!
Failure to do so will result in needless replacement of the air bag system components and repeat service.

 

46-2 CHECK RESISTANCE

Yes
GO to 46-3.

No
REPLACE diagnostic monitor. RECONNECT system. VERIFY system. REACTIVATE system.

 

46-3 ISOLATE CONCERN

  • Disconnect LH primary crash sensor from harness.
  • Measure resistance between Circuit 622 (T/BK) in sensor connector and a nearby, good chassis ground. Make sure that this ground is clean and bare.
  • Is the resistance less than 2 ohms?
Yes
INSPECT Circuit 622 (T/BK) (between Pin 22 and sensor for open circuit. CHECK all interconnects and splices for poor connections. SERVICE any poor connections. RECONNECT system. VERIFY system. REACTIVATE system.

No
REMOVE screws retaining sensor. CLEAN mounting surface of sensor and chassis. INSTALL sensor. TIGHTEN screws to proper specification. GO to 46-4.

 

46-4 CLEAN AND MEASURE RESISTANCE OF SENSOR TO GROUND

  • Measure resistance between Circuit 622 (T/BK) in sensor connector and a good chassis ground.
  • Is resistance less than 2 ohms?
Yes
RECONNECT system. VERIFY system. REACTIVATE system.

No
REPLACE primary crash sensor. RECONNECT system. VERIFY system. REACTIVATE system.