Kalmar - MSARB Seat Buckle Diagnostic

Modified on Thu, 15 Jan at 4:05 PM

1. Fault Overview

A yellow and black circle with black text

AI-generated content may be incorrect. When the LCD screen ‘Fault Detected’ menu option displays a Buckle Fault, and the MSB Fault Light remains constantly illuminated when the ignition is turned to ON (right),

Access MSB and Screen Faults sub-menu by pressing and holding red fault symbol on screen or via holding the menu button for 3 seconds.

The fault conditions will be one of below:

Conditions for setting fault

Faulty belt buckle.
Open/short circuit in the buckle harness.
Internal MSB ECU fault.

NOTE 1: The display will show an “Active” buckle fault under the main screen icon of the LCD (top right-hand corner), and at the same time store the fault.

The buckle fault will not be displayed once the fault becomes “Inactive” under the main screen icon of the LCD.

The red fault symbol will remain until 3x cycles of the Ignition supply OR until the fault is cleared.

After completing diagnosis and rectifying any faults, a full system test must then be performed and documented on the Systems Confirmation Test – MAX-SAFE Anti-Rollaway Brake System test sheet prior to returning the vehicle to service.

2. Diagnostic Procedure

STEP 1: Verify Buckle wiring is connected.

With all connectors will connected, measure voltages at the buckle connector green/white wire (Pin 10). This will need to be completed by back probing the connector. Refer to Table 1.1.

Not within specification: Continue to STEP 2.

Open circuit: Replace belt buckle. Verify repair with Full System Test.

NOTE: The most likely cause of failure is an internal fault within the belt buckle.

Table 1.1

Test	12-volt system
Unbuckled	0V
Buckled	12V
Unbuckled	6V-7V (half reference voltage)

STEP 2: Disconnect the 3-pin buckle connector. Measure between Pin B and Pin C. Verify 12-volt.

(reference voltage).

Measure between Pin A and Pin C. Verify half reference voltage.

Disconnect the black connector (12-pin) at the ECU. Locate the green/white wire (Pin 10). Perform a continuity test of the green/white wire located at the 3-pin buckle connector (Pin A). Refer to Table 2.1.

With the 3-pin buckle connector still disconnected, isolate system by removing fuses.

Measure the resistance of the green/white (Pin 10) wire from the ECU black connector to black (Pin 6). Refer to Table 2.1.

Measure the resistance of the green/white (Pin 10) wire from the ECU black connector to red (Pin 7) wire. Refer to Table 2.1.

Within specifications: The ECU has failed. This scenario is unlikely: repeat all testing again to ensure that it is the ECU that has failed. If all testing has been repeated and testing still indicates that the ECU has failed, replace the ECU.

Verify repair with Full System Test.

Not within specifications: The wiring harness has failed. Replace the wiring harness. Verify repair with Full System Test.

REFIT FUSES AFTER COMPLETION OF TEST.

Table 2.1

Test	12-volt system
Resistance green/white to green/white	Less than 5Ω
Resistance green/white to black (Pin 6).	5.4 kΩ to 5.8 kΩ
Resistance green/white to red (Pin 7).	5.4 kΩ to 5.8 kΩ

3. Full System Test

Undertake a full system test of the MAX-SAFE Brake System and document the results on the test sheet found within the document Systems Confirmation Test – MAX-SAFE Anti-Rollaway Brake System prior to returning the vehicle to service.

Should the testing outlined within the Systems Confirmation Test fail for any reason, the system must be thoroughly inspected, diagnosed, and repaired as per the relevant Diagnostic Process Flow and Procedure document, prior to the vehicle being returned to service.