Diagnostic Trouble Code 45

Center Radiator Primary Crash Sensor Not Mounted To Vehicle Properly

Normal Operation

The diagnostic monitor measures the resistance between Pin 21 (Circuit 620, P/LB) and Pin 3 (diagnostic monitor reference ground). If the diagnostic monitor measures a difference of more than 2.0 ohms between Pin 21 and Pin 3, it will flash out Diagnostic Trouble Code 45.

Note that Circuit 620 (P/LB) is attached to the side of the center radiator primary crash sensor case. In addition, the case is grounded to the vehicle.

Possible Causes

High resistance on Pin 21 (Circuit 620, P/LB) to ground can be caused by:

1. A poor connection due to loose mounting, dirt, or corrosion at the center radiator primary crash sensor mounting location.

2. An open or damaged wire in Circuit 620 (P/LB) from Pin 21 of the diagnostic monitor harness connector to center radiator primary crash sensor.

3. An open circuit inside center radiator primary crash sensor.

DIAGNOSTIC TROUBLE CODE 45

45-1 VERIFY CONDITION

• Turn key to ON.

• Count diagnostic trouble code.

• Is code 45 flashing?

GO to 45-2.

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.

 

45-2 CHECK RESISTANCE

• Deactivate system. Leave positive battery cable disconnected.

• Disconnect diagnostic monitor.

• Set ohmmeter on lowest ohm scale possible (200 ohms or AUTO).

• Zero ohmmeter. RECORD resistance reading with two leads together.

• Measure resistance between Pin 21 (Circuit 620, P/LB) and Pin 3 (ground).

• Subtract reading recorded above.

• Is resistance greater than 2 ohms?
  
  
  
  
  

Yes
GO to 45-3.

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

 

45-3 ISOLATE CONCERN

• Disconnect center radiator primary crash sensor from harness.

• Measure resistance between Circuit 629 (P/LB) 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 620 (P/LB) between Pin 21 and sensor. 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 45-4.

 

45-4 CLEAN AND MEASURE RESISTANCE OF SENSOR TO GROUND

• Measure resistance between Circuit 620 (P/LB) 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.

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