Mercedes-Benz Sprinter / Dodge Sprinter. Service manual — part 88

TEST

ACTION

APPLICABILITY

2

Turn the ignition off.
Inspect the CAB harness connector and affected Wheel Speed Sensor.
Inspect for looseness.
Inspect wiring harness.
Inspect for metal chips on sensor.
Is the Wheel Speed Sensor or CAB harness connector damaged?

All

Yes

→ Repair as necessary.

Perform ABS VERIFICATION TEST - VER 1.

No

→ Go To 3

3

Turn the ignition off.
Inspect the affected Wheel Speed Sensor(s) tone wheel for damage, looseness, or
missing.
NOTE: Refer to the appropriate Service information, if necessary, for
procedures or specifications.
Is the affected tone wheel OK?

All

Yes

→ Go To 4

No

→ Replace the tone wheel in accordance with the Service Informa-

tion.
Perform ABS VERIFICATION TEST - VER 1.

4

Turn the ignition off.
Inspect the affected Wheel Speed Sensor air gap.
NOTE: Refer to the appropriate Service information, if necessary, for
procedures or specifications.
Is the affected air gap OK?

All

Yes

→ Go To 5

No

→ Repair as necessary.

Perform ABS VERIFICATION TEST - VER 1.

5

Turn the ignition off.
Inspect the affected Wheel Speed Sensor(s) wheel bearing.
NOTE: Refer to the appropriate Service information, if necessary, for
procedures or specifications.
Is the affected wheel bearing clearance OK?

All

Yes

→ Go To 6

No

→ Repair as necessary.

Perform ABS VERIFICATION TEST - VER 1.

6

Turn the ignition off.
Visually inspect the brakes for locking up due to lining contamination or overheating.
Inspect all brake components for defects which would cause a speed difference.
Were any problems found?

All

Yes

→ Repair as necessary.

Perform ABS VERIFICATION TEST - VER 1.

No

→ Go To 7

47

BRAKES (CAB)

LEFT FRONT WHEEL SPEED SENSOR SIGNAL —

Continued

TEST

ACTION

APPLICABILITY

7

Turn the ignition off.
Disconnect the Anti-Lock Brake module harness connector.
Connect a voltmeter to the Wheel Speed Sensor (+) and (-) circuits at the Antilock
Brake module harness connector.
Rotate the wheel at a speed of at least one revolution per second while monitoring the
voltage.
Is the AC voltage fluctuating above 120 mV?

All

Yes

→ Replace the Controller Antilock Brake in accordance with the

Service Information.
Perform ABS VERIFICATION TEST - VER 1.

No

→ Replace the affected Wheel Speed Sensor in accordance with the

Service Information.
Perform ABS VERIFICATION TEST - VER 1.

8

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.
Look for any wiring conditions that may cause electromagnetic interference with the
Wheel Speed Sensor circuits.
Inspect Wheel Speed sensors, Tone Wheels, Brake Rotors, Wheel Bearings, etc, for
conditions that may cause speed variations from wheel to wheel.
Were any problems found?

All

Yes

→ Repair as necessary.

Perform ABS VERIFICATION TEST - VER 1.

No

→ Test Complete.

48

BRAKES (CAB)

LEFT FRONT WHEEL SPEED SENSOR SIGNAL —

Continued

Symptom:

NO COMMUNICATION WITH BUS

When Monitored and Set Condition:

NO COMMUNICATION WITH BUS

When Monitored:

Ignition On - Continuously

Set Condition:

When the CAB fails to receive all module messages.

POSSIBLE CAUSES

CAN CIRCUITS SHORTED TO VOLTAGE

MODULE SHORT TO VOLTAGE

CAN CIRCUITS SHORTED TO GROUND

MODULE SHORT TO GROUND

CAN CIRCUITS SHORTED TOGETHER

ENGINE CONTROL MODULE

SENTRY KEY REMOTE ENTRY MODULE

TEST

ACTION

APPLICABILITY

1

Turn the ignition off.
Disconnect the Instrument Cluster harness connectors.
Turn the ignition on.
Measure the voltage between CAN C Bus (+) circuit and ground.
Measure the voltage between CAN C Bus (-) circuit and ground.
Is the voltage above 3.0 volts on either circuit?

All

Yes

→ Go To 2

No

→ Go To 3

49

BRAKES (CAB)

TEST

ACTION

APPLICABILITY

2

Turn the ignition off.
Using a voltmeter, connect one end to the CAN circuit that previously measured
above 3.0 volts, and the other end to ground.
NOTE: Refer to the wiring diagrams in the service information to help
determine which modules are connected to the CAN Bus.
NOTE: Wait one minute, after turning the ignition off, before disconnecting
the module.
Disconnect a module that is connected to the CAN bus.
Turn the ignition on.
Monitor and note the voltmeter reading.
Repeat this procedure until either the voltage reading drops below 3.0 volts or all
modules that are connected to the CAN Bus are disconnected and the voltage reading
remains above 3.0 volts. Then, proceed to the conclusion question.
What is the outcome?

All

> 3.0 volts w/all modules disconnected

Repair the CAN C Bus (+) circuit or the CAN C Bus (-) circuit for
a short to voltage.
Perform BODY VERIFICATION TEST - VER 1.

< 3.0 volts after disconnecting a module

Replace the module that caused the voltage reading to drop after
disconnecting it.
Perform BODY VERIFICATION TEST - VER 1.

3

Turn the ignition off.
Disconnect the Instrument Cluster harness connectors.
Disconnect the negative battery cable.
Measure the resistance between ground and the CAN C Bus (+) circuit.
Measure the resistance between ground and the CAN C Bus (-) circuit.
Is the resistance below 50.0 ohms on either circuit?

All

Yes

→ Go To 4

No

→ Go To 5

4

Turn the ignition off.
Disconnect the negative battery cable.
Using an ohmmeter, connect one end to the CAN Bus circuit that previously
measured below 50.0 ohms and the other end to ground.
NOTE: Refer to the wiring diagrams in the service information to help
determine which modules are connected to the CAN Bus.
Disconnect a module that is connected to the CAN Bus.
Monitor and note the ohmmeter reading.
Repeat this procedure until either the resistance reading goes above 50.0 ohms or all
modules that are connected to the CAN Bus are disconnected and the resistance
reading remains below 50.0 ohms. Then, proceed to the conclusion question.
What is the outcome?

All

< 50.0 ohms w/all modules disconnected

Repair the CAN C Bus (+) circuit or the CAN C Bus (-) circuit for
a short to ground.
Perform BODY VERIFICATION TEST - VER 1.

>50.0 ohms after disconnecting a module

Replace the module that caused the resistance reading to increase
after disconnecting it.
Perform BODY VERIFICATION TEST - VER 1.

50

BRAKES (CAB)

NO COMMUNICATION WITH BUS —

Continued