Mercedes-Benz Sprinter / Dodge Sprinter. Service manual — part 81

TEST

ACTION

APPLICABILITY

6

Turn the ignition off.
Disconnect the appropriate brake switch harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Fused Ignition Switch
Output circuit at the harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Is the test light illuminated and bright?

All

Yes

→ Go To 7

No

→ Repair the Fused Ignition Switch Output circuit for an open.

Perform ABS VERIFICATION TEST - VER 1.

7

Turn the ignition off.
Disconnect the CAB harness connector.
Disconnect the appropriate brake switch harness connector.
Turn the ignition on.
Measure the voltage of the output circuit at the brake switch harness connector.
NOTE: Measurement is taken at the Brake Switch Output circuit or the
Brake Lamp Output circuit as determined by the previously performed
switch test.
Is there any voltage present?

All

Yes

→ Repair the affected circuit for a short to voltage.

Perform ABS VERIFICATION TEST - VER 1.

No

→ Go To 8

8

Turn the ignition off.
Disconnect the CAB harness connector.
Disconnect the appropriate brake switch harness connector.
Measure the resistance between ground and switch output circuit at the switch
connector.
NOTE: Measurement is taken at the Brake Switch Output circuit or the
Brake Lamp Output circuit as determined by the previously performed
switch test.
Is the resistance below 5.0 ohms?

All

Yes

→ Repair the affected circuit for a short to ground.

Perform ABS VERIFICATION TEST - VER 1.

No

→ Go To 9

9

Turn the ignition off.
Disconnect the CAB harness connector.
Disconnect the appropriate brake switch harness connector.
Measure the resistance of the output circuit between the switch harness connector
and the CAB harness connector.
NOTE: Measurement is taken at the Brake Switch Output circuit or the
Brake Lamp Output circuit as determined by the previously performed
switch test.
Is the resistance above 5.0 ohms?

All

Yes

→ Repair the affected circuit for an open.

Perform ABS VERIFICATION TEST - VER 1.

No

→ Go To 10

19

BRAKES (CAB)

BRAKE SWITCH CIRCUIT —

Continued

TEST

ACTION

APPLICABILITY

10

Turn the ignition off.
Disconnect the CAB harness connector.
Disconnect the C1 Brake Switch and C2 Brake Lamp Switch harness connectors.
Measure the resistance between the Brake Switch Output circuit and Brake Lamp
Switch Output circuit in the C1 and C2 connectors.
Is the resistance below 5.0 ohms?

All

Yes

→ Repair the Brake Switch Output circuit for a short to the Brake

Lamp Switch Output circuit.
Perform ABS VERIFICATION TEST - VER 1.

No

→ Replace the Controller Antilock Brake in accordance with the

Service Information.
Perform ABS VERIFICATION TEST - VER 1.

20

BRAKES (CAB)

BRAKE SWITCH CIRCUIT —

Continued

Symptom:

CAB CHECK SUM

When Monitored and Set Condition:

CAB CHECK SUM

When Monitored:

Ignition On - Once

Set Condition:

When the sum of all storage bytes are not equal to the original sum stored.

POSSIBLE CAUSES

INTERMITTENT CAB CHECK SUM DTC

DAMAGED CAB/CAB HARNESS CONNECTOR

FUSED OPTIONAL EQUIPMENT RELAY OUTPUT CIRCUIT OPEN

FUSED B(+) CIRCUIT OPEN

GROUND CIRCUIT OPEN

ANTI-LOCK BRAKE CONTROLLER

TEST

ACTION

APPLICABILITY

1

Turn the ignition on.
With the DRBIII

t, read DTCs.

With the DRBIII

t, erase DTCs.

Turn the ignition off.
Turn the ignition on.
With the DRBIII

t, read DTCs.

Does the DRBIII

t display CAB CHECK SUM?

All

Yes

→ Go To 2

No

→ Go To 6

2

Turn the ignition off.
Disconnect the CAB harness connector.
Inspect the CAB/CAB harness connector for damage.
Is there any broken, bent, pushed out, corroded or spread terminals?

All

Yes

→ Repair as necessary.

Perform ABS VERIFICATION TEST - VER 1.

No

→ Go To 3

21

BRAKES (CAB)

TEST

ACTION

APPLICABILITY

3

Turn the ignition off.
Disconnect the CAB harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Fused Optional Equipment
Relay Output circuit at the CAB harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?

All

Yes

→ Go To 4

No

→ Repair the Fused Optional Equipment Relay Output circuit for an

open.
Perform ABS VERIFICATION TEST - VER 1.

4

Turn the ignition off.
Disconnect the CAB harness connector.
Using a 12-volt test light connected to ground, check both Fused B(+) circuits at the
CAB harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?

All

Yes

→ Go To 5

No

→ Repair the Fused B(+) circuit for an open.

Perform ABS VERIFICATION TEST - VER 1.

5

Turn the ignition off.
Disconnect the CAB harness connector.
Using a 12-volt test light connected to 12-volts, check the CAB harness connector
Ground circuits.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?

All

Yes

→ Replace the Controller Antilock Brake in accordance with the

Service Information.
Perform ABS VERIFICATION TEST - VER 1.

No

→ Repair the Ground circuit for an open.

Perform ABS VERIFICATION TEST - VER 1.

6

Turn the ignition off.
Visually inspect the related wiring harness.
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out, or corroded terminals.
Were any problems found?

All

Yes

→ Repair as necessary.

Perform ABS VERIFICATION TEST - VER 1.

No

→ Test Complete.

22

BRAKES (CAB)

CAB CHECK SUM —

Continued