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Ford Falcon. Manual - part 471

501-20b-99

Occupant Restraints — Passive

501-20b-99

DIAGNOSIS AND TESTING (Continued)

Pinpoint Test O: LFC 52/DTC B2438 - Passenger Safety Belt Buckle Switch Circuit

Short to Ground

Normal Operation

The restraints control module (RCM) checks the passenger safety belt buckle switch circuits for faults. If the

RCM detects a short to ground fault, it will store diagnostic trouble code (DTC) B2438 in memory and flash

lamp fault code (LFC) 52 (or higher priority code if one exists) on the airbag indicator.

Possible Causes

A passenger safety belt buckle switch circuit fault can be caused by:

damaged wiring, terminals, or connectors.
a faulty passenger safety belt buckle switch.
a faulted RCM.

PINPOINT TEST O : LFC 52/DTC B2438 - PASSENGER SAFETY BELT BUCKLE SWITCH CIRCUIT

SHORT TO GROUND

Test Step

Result / Action to Take

CHECK FOR A HARD OR INTERMITTENT DTC

Enter the following diagnostic mode on the diagnostic tool:

Yes

This is a hard fault. The fault condition is still

Retrieve Continuous DTCs

present. This fault cannot be cleared until it is

Retrieve and record any continuous DTCs for use later in this pinpoint corrected and the DTC is no longer retrieved

test.

during the on-demand self test. Go to O2.

Enter the following diagnostic mode on the diagnostic tool:

On-Demand Self Test

This is an intermittent fault. The fault condition is
not present at this time. Go to O5.

Was DTC B2438 retrieved during the on-demand self test?

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501-20b-100

Occupant Restraints — Passive

501-20b-100

DIAGNOSIS AND TESTING (Continued)

Test Step

Result / Action to Take

CHECK CIRCUIT 1514 (R/B) FOR A SHORT TO GROUND

BETWEEN THE RCM AND THE PASSENGER SAFETY

BELT BUCKLE SWITCH

Yes

WARNING:

If the supplemental restraint system (SRS) is

Go to O3.

being serviced, the system must be deactivated and restraint system

diagnostic tools must be installed. Refer to Airbag and Safety Belt

REPAIR circuit 1514 (R/B). Go to O6.

Pretensioner Supplemental Restraint System (SRS) in this section.
The airbag restraint system diagnostic tools must be removed and
the airbag modules reconnected when the system is reactivated to
avoid non-deployment in a collision, resulting in possible personal
injury.

WARNING:

Never probe the connectors on the airbag

module. Doing so can result in airbag deployment, which can result in
personal injury.

WARNING:

The safety belt buckle pretensioner is a

pyrotechnic device. Never probe a pretensioner electrical connector.
Doing so could result in pretensioner or airbag deployment and could
result in personal injury.

WARNING:

Never probe the electrical connector on a side

airbag module. Doing so can result in side airbag deployment.

NOTE:

Diagnostics or repairs are not to be performed on a seat

equipped with a seat side airbag with the seat in the vehicle. Prior to
attempting to diagnose or repair a seat concern when equipped with a seat
side airbag, the seat must be removed from the vehicle and the restraint
system diagnostic tools must be installed in the seat side airbag electrical
connectors. The restraint system diagnostic tools must be removed
prior to operating the vehicle over the road.

NOTE:

After diagnosing or repairing an SRS, the restraint system

diagnostic tools must be removed before operating the vehicle over
the road.

NOTE:

After diagnosing or repairing a seat system, the restraint system

diagnostic tools must be removed before operating the vehicle over
the road.

NOTE:

The SRS must be fully operational and free of faults before

releasing the vehicle to the customer.

Key in OFF position.

Deactivate the system. Refer to Airbag and Safety Belt Pretensioner
Supplemental Restraint System (SRS) in the Diagnosis and Testing
portion of this section.

Key in OFF position.

Disconnect Passenger Safety Belt Buckle Switch C234.

Disconnect RCM C189b.

Measure the resistance between RCM C189b pin 26, circuit 1514
(R/B), harness side and ground.

Is the resistance greater than 1,000,000 ohms?

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501-20b-101

Occupant Restraints — Passive

501-20b-101

DIAGNOSIS AND TESTING (Continued)

Test Step

Result / Action to Take

CHECK THE PASSENGER SAFETY BELT BUCKLE

SWITCH

Connect Passenger Safety Belt Buckle Switch C234 to the safety belt

Yes

buckle.

Go to O4.

Connect RCM C189b.

INSTALL a new passenger safety belt buckle

Key in ON position.

and pretensioner assembly. Go to O6.

NOTE:

With the safety belt buckled, the current should measure

11.0-19.4 mA. With the safety belt unbuckled, the current should
measure 3.9-6.9 mA.

Measure the current flow from the passenger safety belt buckle switch
C234, circuit 1514 (R/B), harness side to component side, with the
safety belt buckled and again unbuckled.

Is the current between 11.0-19.4 mA with the safety belt buckled
and between 3.9-6.9 mA with the safety belt unbuckled?

CONFIRM THE RCM FAULT

Yes

NOTE:

Make sure all restraint system diagnostic tools, sensor electrical

INSTALL a new RCM. REFER to Restraints

connectors, and the RCM electrical connector are connected before

Control Module (RCM) in this section. Go to O6.

carrying out the on-demand self test. If not, erroneous DTCs will be
recorded.

Fault corrected. Go to O6.

Connect Passenger Safety Belt Buckle Switch C234.

Enter the following diagnostic mode on the diagnostic tool:
On-Demand Self Test

Was DTC B2438 retrieved during the on-demand self test?

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501-20b-102

Occupant Restraints — Passive

501-20b-102

DIAGNOSIS AND TESTING (Continued)

Test Step

Result / Action to Take

CHECK FOR AN INTERMITTENT FAULT

Yes

WARNING:

If the supplemental restraint system (SRS) is

Go to O2.

being serviced, the system must be deactivated and restraint system

diagnostic tools must be installed. Refer to Airbag and Safety Belt

CHECK for causes of the intermittent fault.

Pretensioner Supplemental Restraint System (SRS) in this section.

ATTEMPT to recreate the hard fault by flexing

The airbag restraint system diagnostic tools must be removed and

the wire harness and cycling the ignition key

the airbag modules reconnected when the system is reactivated to

frequently. REPAIR any intermittent concerns

avoid non-deployment in a collision, resulting in possible personal

found. Go to O6.

injury.

WARNING:

Never probe the connectors on the airbag

module. Doing so can result in airbag deployment, which can result in
personal injury.

WARNING:

The safety belt buckle pretensioner is a

pyrotechnic device. Never probe a pretensioner electrical connector.
Doing so could result in pretensioner or airbag deployment and could
result in personal injury.

WARNING:

Never probe the electrical connector on a side

airbag module. Doing so can result in side airbag deployment.

NOTE:

Diagnostics or repairs are not to be performed on a seat

NOTE:

After diagnosing or repairing an SRS, the restraint system

diagnostic tools must be removed before operating the vehicle over
the road.

NOTE:

After diagnosing or repairing a seat system, the restraint system

diagnostic tools must be removed before operating the vehicle over
the road.

NOTE:

The SRS must be fully operational and free of faults before

releasing the vehicle to the customer.

Key in OFF position.

Deactivate the system. Do not remove the seat at this time. Refer to
Airbag and Safety Belt Pretensioner Supplemental Restraint System
(SRS) in the Diagnosis and Testing portion of this section.

Enter the following diagnostic mode on the diagnostic tool:
On-Demand Self Test

Was DTC B2438 retrieved during the on-demand self test?

CHECK FOR ADDITIONAL DTCs

Refer to the continuous DTCs recorded during Step O1.

Yes

Do not clear any DTCs until all DTCs have been

Were any continuous DTCs retrieved during Step O1?

resolved. GO to the Restraints Control Module
(RCM) Diagnostic Trouble Code (DTC) Table in
this section for pinpoint test direction.

RECONNECT the system. REACTIVATE the
system. PROVE OUT the system. REFER to
Airbag and Safety Belt Pretensioner
Supplemental Restraint System (SRS). CLEAR
all DTCs.

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