Content .. 78 79 80 81 ..

Mercedes-Benz Sprinter / Dodge Sprinter. Manual - part 80

Symptom:

BRAKE PRESSURE SENSOR CIRCUIT

POSSIBLE CAUSES

BRAKE PRESSURE SENSOR CIRCUIT INTERMITTENT DTC

BRAKE PRESSURE SENSOR CIRCUIT SHORT TO VOLTAGE

BRAKE PRESSURE SENSOR CIRCUIT SHORT TO GROUND

BRAKE PRESSURE SENSOR CIRCUIT OPEN

BRAKE PRESSURE SENSOR

ANTI-LOCK BRAKE CONTROLLER

TEST

ACTION

APPLICABILITY

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

t, read DTCs. Record DTC information.

NOTE: If a system undervoltage or overvoltage DTC is set along with this
DTC, diagnose the system voltage DTC first.
NOTE: Before continuing, make sure that the Brake Lamp switch is ad-
justed correctly and functioning properly. Adjust or replace the switch as
necessary in accordance with the Service Information.
With the DRBIII

t, erase DTCs.

Road test the vehicle and perform several braking maneuvers.
With the DRBIII

t, read DTCs.

Does this DTC reset?

All

Yes

→ Go To 2

→ Go To 6

Turn the ignition off.
Disconnect the Brake Pressure Sensor harness connector.
Disconnect the CAB harness connector.
Turn the ignition on.
Measure the voltage of the Brake Pressure Sensor signal circuit.
Measure the voltage of the Brake Pressure Sensor ground circuit.
Measure the voltage of the Brake Pressure Sensor 5 volt supply circuit.
Is there voltage present on any of the circuits?

All

Yes

→ Repair the Brake Pressure Sensor circuit(s) for a short to voltage.

→ Go To 3

Turn the ignition off.
Disconnect the Brake Pressure Sensor harness connector.
Disconnect the CAB harness connector.
Measure the resistance between ground and the Brake Pressure Sensor signal
circuit.
Measure the resistance between ground and the Brake Pressure Sensor 5 volt supply
circuit.
Is the resistance below 5.0 ohms for either circuit?

All

Yes

→ Repair the Brake Pressure Sensor circuit(s) for a short to ground.

→ Go To 4

BRAKES (CAB)

TEST

ACTION

APPLICABILITY

Turn the ignition off.
Disconnect the Brake Pressure Sensor harness connector.
Disconnect the CAB harness connector.
Measure the resistance of the Brake Pressure Sensor signal circuit.
Measure the resistance of the Brake Pressure Sensor ground circuit.
Measure the resistance of the Brake Pressure Sensor 5 volt supply circuit.
Is the resistance above 5.0 ohms for any of the circuits?

All

Yes

→ Repair the Brake Pressure Sensor circuit(s) for an open

→ Go To 5

Turn the ignition off.
Disconnect the Brake Pressure Sensor harness connector.
Inspect the harness and connectors related to this circuit. If any problems are found,
repair as necessary.
If no problems are found, replace the Brake Pressure Sensor in accordance with the
Service Information.
With the DRBIII

t, clear DTCs.

Road test the vehicle and perform several braking maneuvers.
With the DRBIII

t, read DTCs.

Does this DTC reset?

All

Yes

→ Replace the CAB in accordance with the Service Information.

→ Test Complete.

The condition that set this DTC is not present at this time.
Monitor the DRBIII

t while wiggle testing the related harness and connectors. Look

for any related parameters to change or for the DTC to reset.
Inspect the related harness and connectors.
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.

→ Test Complete.

BRAKES (CAB)

BRAKE PRESSURE SENSOR CIRCUIT —

Continued

Symptom:

BRAKE SWITCH CIRCUIT

When Monitored and Set Condition:

BRAKE SWITCH CIRCUIT

When Monitored:

Ignition On - Continuously

Set Condition:

When the brake lamp switch and brake switch outputs are both open or

shorted.

POSSIBLE CAUSES

INTERMITTENT BRAKE SWITCH CIRCUIT DTC

BRAKE LAMP SWITCH STATUS

BRAKE SWITCH STATUS

FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN

OUTPUT CIRCUIT SHORT TO VOLTAGE

OUTPUT CIRCUIT SHORT TO GROUND

OUTPUT CIRCUIT OPEN

BRAKE SWITCH OUTPUT CIRCUIT SHORT TO BRAKE LAMP SWITCH OUTPUT CIRCUIT

BRAKE LAMP SWITCH

BRAKE SWITCH

ANTI-LOCK BRAKE CONTROLLER

TEST

ACTION

APPLICABILITY

NOTE: This DTC will set if the Brake Switch, the Brake Lamp Switch, or
both switches are inoperative. It will be necessary to verify the functional-
ity of each switch.
NOTE: If the Brake Switch and the Brake Lamp Switch are inoperative, it
will be necessary to diagnose BOTH circuits.
Turn the ignition off.
Turn the ignition on.
With the DRBIII

t in Inputs/Outputs, monitor the Brake Lamp Switch state while

pressing and releasing the brake pedal.
Does the DRBIII

t display change from OPEN to CLOSED as the brake pedal is

pressed and released?

All

Yes

→ Go To 2

→ Go To 5

BRAKES (CAB)

TEST

ACTION

APPLICABILITY

t in Inputs/Outputs, monitor the Brake Switch state while pressing

and releasing the brake pedal.
Does the DRBIII

t display change from CLOSED to OPEN as the brake pedal is

pressed and released?

All

Yes

→ Go To 3

→ Go To 4

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.

→ Test Complete.

Turn the ignition off.
Disconnect the C1 Brake Switch harness connector.
Turn the ignition on.
With the DRBIII

t in Inputs/Outputs, monitor the Brake Switch state.

Connect a jumper wire between the Fused Ignition Switch Output circuit and Brake
Switch Output circuit in the C1 Brake Switch harness connector.
Does the DRBIII

t display a change from OPEN to CLOSED?

All

Yes

→ Replace the Brake Switch in accordance with the Service Infor-

mation.
Perform ABS VERIFICATION TEST - VER 1.

→ Go To 6

Turn the ignition off.
Disconnect the C2 Brake Lamp Switch harness connector.
Turn the ignition on.
With the DRBIII

t in Inputs/Outputs, monitor the Brake Lamp Switch state.

Connect a jumper wire between the Fused Ignition Switch Output circuit and Brake
Lamp Switch Output circuit in the C2 Brake Lamp Switch harness connector.
Does the DRBIII

t display a change from OPEN to CLOSED?

All

Yes

→ Replace the Brake Lamp Switch in accordance with the Service

Information.
Perform ABS VERIFICATION TEST - VER 1.

→ Go To 6

BRAKES (CAB)

BRAKE SWITCH CIRCUIT —

Continued

Content .. 78 79 80 81 ..