2006 MERCEDES-BENZ SPRINTER engine

Symptom:
DOSING PUMP SHORTED
POSSIBLE CAUSES
DOSING PUMP SHORTED TO GROUND
DOSING PUMP CONTROL CIRCUIT SHORTED TO GROUND CIRCUIT
DOSING PUMP CONTROL CIRCUIT SHORTED TO GROUND
CABIN HEATER OR HEATER BOOSTER CONTROL UNIT
TEST ACTION APPLICABILITY
1WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO COOL BEFORE PER-
FORMING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL
INJURY OR DEATH.
CAUTION: DO NOT PERFORM THIS TEST UNLESS DIRECTED HERE BY
THE HEATER PRE-TEST. ALWAYS PERFORM THE HEATER PRE-TEST
PRIOR TO PERFORMING ANY OTHER TEST FOR THE RESULT TO BE
VALID.
Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Dosing Pump harness connector.
Turn the ignition on.
Verify that the Cabin Heater or Heater Booster is switched off.
Set the blend control to the max heat position and the mode control to the floor
position.
With the DRBIIIt, erase the Cabin Heater or Heater Booster Module's DTCs.
Start the engine. Allow the engine to idle.
With the DRBIII, monitor for Cabin Heater or Heater Booster Module DTCs while
performing the following step.
NOTE: Do not disconnect the vehicle's battery or the heater's main power
supply while the heater is in operation or in run-down mode. Failure to
follow these instructions can result in excess emissions from the heater
during heater operation.
Switch the Cabin Heater or Heater Booster on. If necessary, allow the heater to run
through at least one cycle of operation (approximately 10 minutes), and then switch
the heater off.
Turn the engine off.
Does the DRBIIItdisplay: DOSING PUMP HIGH OR OPEN?All
Ye s!Replace the Dosing Pump in accordance with the Service Infor-
mation.
Perform HEATER VERIFICATION TEST - VER 1.
No!Go To 2
81
CABIN HEATER

TEST ACTION APPLICABILITY
2WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO COOL BEFORE PER-
FORMING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL
INJURY OR DEATH.
Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Cabin Heater harness connector.
Remove the Fan Stage 1 Relay from the relay center.
Measure the resistance of the Fan Stage 1 Relay High Side Control circuit between
the Cabin Heater harness connector and the relay center (Fan Stage 1 Relay
connector terminal 86).
Is the resistance below 5.0 ohms?All
Ye s!Go To 3
No!Repair the Fan Stage 1 Relay High Side Control circuit for an
open.
Perform HEATER VERIFICATION TEST - VER 1.
3WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
Turn the ignition off.
Reconnect the Cabin Heater harness connector.
Install a substitute relay in place of the Fan Stage 1 Relay.
Turn the ignition on.
Verify that the Cabin Heater is switched off.
Set the blend control to the max heat position and the mode control to the floor
position.
With the DRBIIIt, erase the Cabin Heater Module's DTCs.
Start the engine. Allow the engine to idle.
With the DRBIII, monitor for Cabin Heater Module DTCs while performing the
following step.
NOTE: Do not disconnect the vehicle's battery or the heater's main power
supply while the heater is in operation or in run-down mode. Failure to
follow these instructions can result in excess emissions from the heater
during heater operation.
Switch the Cabin Heater on. If necessary, allow the heater to run through at least one
cycle of operation (approximately 10 minutes), and then switch the heater off.
Turn the engine off.
Does the DRBIIItdisplay: FAN STAGE 1 RELAY CONTROL OPEN?All
Ye s!Replace the Cabin Heater Assembly in accordance with the
Service Information. Reinstall the original Fan Stage 1 Relay.
Perform HEATER VERIFICATION TEST - VER 1.
No!Replace the original Fan Stage 1 Relay in accordance with the
Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
84
CABIN HEATER
FAN STAGE 1 RELAY CONTROL OPEN ÐContinued

Symptom:
FAN STAGE 1 RELAY CONTROL SHORTED
POSSIBLE CAUSES
FAN STAGE 1 RELAY
FAN STAGE 1 RELAY HIGH SIDE CONTROL CIRCUIT SHORTED TO GROUND
FAN STAGE 1 RELAY HIGH SIDE CONTROL CIRCUIT SHORTED TO GROUND CIRCUIT
CABIN HEATER CONTROL UNIT
TEST ACTION APPLICABILITY
1WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
CAUTION: DO NOT PERFORM THIS TEST UNLESS DIRECTED HERE BY
THE HEATER PRE-TEST. ALWAYS PERFORM THE HEATER PRE-TEST
PRIOR TO PERFORMING ANY OTHER TEST FOR THE RESULT TO BE
VALID.
Turn the ignition off.
Install a substitute relay in place of the Fan Stage 1 Relay.
Turn the ignition on.
Verify that the Cabin Heater is switched off.
Set the blend control to the max heat position and the mode control to the floor
position.
With the DRBIIIt, erase the Cabin Heater Module's DTCs.
Start the engine. Allow the engine to idle.
With the DRBIII, monitor for Cabin Heater Module DTCs while performing the
following step.
NOTE: Do not disconnect the vehicle's battery or the heater's main power
supply while the heater is in operation or in run-down mode. Failure to
follow these instructions can result in excess emissions from the heater
during heater operation.
Switch the Cabin Heater on. If necessary, allow the heater to run through at least one
cycle of operation (approximately 10 minutes), and then switch the heater off.
Turn the engine off.
Does the DRBIIItdisplay: FAN STAGE 1 RELAY CONTROL SHORTED?All
Ye s!Go To 2
No!Replace the original Fan Stage 1 Relay in accordance with the
Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
85
CABIN HEATER

Symptom List:
HEATER IN LOCKOUT MODE
HEATER OVERHEATED
SUCCESSIVE OVERHEATING
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be HEATER IN LOCKOUT MODE.
When Monitored and Set Condition:
HEATER IN LOCKOUT MODE
When Monitored: During heater activation and operation.
Set Condition: This DTC will set if multiple attempts to start the heater have failed or if
successive overheating occurs.
HEATER OVERHEATED
When Monitored: After heater activation, when the system is in a steady state of
operation.
Set Condition: This DTC will set if the Temperature Sensor's resistance or Overheating
Sensor's resistance is not within the expected parameters (coolant temperature in the
heater module exceeds 105ÉC [221ÉF]).
SUCCESSIVE OVERHEATING
When Monitored: After heater activation, when the system is in a steady state of
operation.
Set Condition: This DTC will set if successive overheating occurs.
POSSIBLE CAUSES
CABIN HEATER ASSEMBLY OR HEATER BOOSTER ASSEMBLY
HEATER'S COOLANT HOSES RESTRICTED/LEAKING/DAMAGED
ENGINE'S COOLING SYSTEM FAULT
CABIN HEATER OR HEATER BOOSTER CONTROL UNIT
HEATER OVERHEATED/SUCCESSIVE OVERHEATING CLEARED, ADDITIONAL DTC(S)
PRESENT
93
CABIN HEATER

TEST ACTION APPLICABILITY
1WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO COOL BEFORE PER-
FORMING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL
INJURY OR DEATH.
CAUTION: DO NOT PERFORM THIS TEST UNLESS DIRECTED HERE BY
THE HEATER PRE-TEST. ALWAYS PERFORM THE HEATER PRE-TEST
PRIOR TO PERFORMING ANY OTHER TEST FOR THE RESULT TO BE
VALID.
Turn the ignition off.
NOTE: If there is an internal leak in the heater, a continuous loud chunking
or grinding noise may have been heard coming from the assembly during
the Pre-test.
Check for engine coolant continuously flowing out of the heater's exhaust pipe.
Is engine coolant coming out of the heater's exhaust pipe?All
Ye s!Replace the Cabin Heater Assembly or Heater Booster Assembly
in accordance with the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
No!Go To 2
2WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO COOL BEFORE PER-
FORMING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL
INJURY OR DEATH.
Turn the ignition off.
Inspect the heater's coolant hoses for restrictions, leakage, and damage.
Are the heater's coolant hoses Ok?All
Ye s!Go To 3
No!Repair the heater's coolant hoses as necessary in accordance with
the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
3WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
Check that the engine's cooling system is operating properly in accordance with the
Service Information.
Is the engine's cooling system operating properly?All
Ye s!Go To 4
No!Repair the engine's cooling system in accordance with the Service
Information.
Perform HEATER VERIFICATION TEST - VER 1.
94
CABIN HEATER
HEATER IN LOCKOUT MODE ÐContinued

TEST ACTION APPLICABILITY
4WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
Refill the cooling system in accordance with the Service Information.
Start the engine.
Allow the engine to reach normal operating temperature.
Turn the engine off.
Allow the engine coolant to cool down to a temperature of 50ÉC (122ÉF).
Start the engine.
Allow the engine to reach normal operating temperature.
Turn the engine off.
View repairAll
Repair
Go To 5
5WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
NOTE: The heater's control unit will store up to five DTCs in its memory.
NOTE: If the heater's control unit detects a new fault in the system, one that
is not already stored in its memory, it will clear the oldest of the five stored
DTCs, and it will store the new fault's DTC.
NOTE: If the heater's control unit detects a reoccurrence of a stored fault,
it will overwrite that fault's DTC with the most recent occurrence.
Turn the ignition on.
Verify that the Cabin Heater or Heater Booster is switched off.
Set the blend control to the max heat position and the mode control to the floor
position.
Start the engine. Allow the engine to idle.
With the DRBIII, monitor for Cabin Heater or Heater Booster Module DTCs while
performing the following step.
NOTE: Do not disconnect the vehicle's battery or the heater's main power
supply while the heater is in operation or in run-down mode. Failure to
follow these instructions can result in excess emissions from the heater
during heater operation.
Switch the Cabin Heater or Heater Booster on. If necessary, allow the heater to run
through at least one cycle of operation (approximately 10 minutes), and then turn the
heater off.
Turn the engine off.
Does the DRBIIItdisplay any DTCs?All
Overheating Related DTC(s) Reset
Replace the Cabin Heater Assembly or Heater Booster Assembly
in accordance with the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
Ovrheatng DTC(s) clear, Other DTC(s) Set
Return to the symptom list and choose the symptom(s).
Perform HEATER VERIFICATION TEST - VER 1.
No DTCs Present
Test Complete.
95
CABIN HEATER
HEATER IN LOCKOUT MODE ÐContinued

Symptom:
OVER VOLTAGE
When Monitored and Set Condition:
OVER VOLTAGE
When Monitored: With the engine running.
Set Condition: This DTC will set if the heater's power supply exceed 15.9 volts for longer
than 20 seconds.
POSSIBLE CAUSES
VEHICLE'S CHARGING SYSTEM OVERCHARGING
CABIN HEATER OR HEATER BOOSTER CONTROL UNIT
TEST ACTION APPLICABILITY
1WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
WARNING: ALLOW THE HEATER ASSEMBLY TO COOL BEFORE PER-
FORMING A COMPONENT INSPECTION/REPAIR/REPLACEMENT. FAIL-
URE TO FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL
INJURY OR DEATH.
CAUTION: DO NOT PERFORM THIS TEST UNLESS DIRECTED HERE BY THE
HEATER PRE-TEST. ALWAYS PERFORM THE HEATER PRE-TEST PRIOR TO
PERFORMING ANY OTHER TEST FOR THE RESULT TO BE VALID.
Check the vehicle's charging system for proper operation in accordance with the
Service Information.
Is the vehicle's charging system operating properly?All
Ye s!Replace the Cabin Heater Assembly or Heater Booster Assembly
in accordance with the Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
No!Repair the vehicle's charging system in accordance with the
Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
96
CABIN HEATER

Symptom:
UNDER VOLTAGE
When Monitored and Set Condition:
UNDER VOLTAGE
When Monitored: With the engine running.
Set Condition: This DTC will set if the heater's power supply voltage drops below 10.2
volts for longer than 20 seconds.
POSSIBLE CAUSES
VEHICLE'S BATTERY SYSTEM
VEHICLE'S CHARGING SYSTEM NOT OPERATING PROPERLY
CABIN HEATER OR HEATER BOOSTER CONTROL UNIT
FUSED B+ CIRCUIT HIGH RESISTANCE
CABIN HEATER OR HEATER BOOSTER CONTROL UNIT
TEST ACTION APPLICABILITY
1WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
Turn the ignition off.
Inspect the vehicle's battery terminals, cable terminals, and cables for corrosion and
damage in accordance with the Service Information.
Test the vehicle's battery in accordance with the Service Information.
Is the vehicle's battery system Ok?All
Ye s!Go To 2
No!Clean/repair the vehicle's battery system in accordance with the
Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
2WARNING: NEVER OPERATE THE HEATER IN AN ENCLOSED AREA
THAT DOES NOT HAVE EXHAUST VENTILATION FACILITIES. ALWAYS
VENT THE EXHAUST WHEN OPERATING THE HEATER. FAILURE TO
FOLLOW THESE INSTRUCTIONS CAN RESULT IN PERSONAL INJURY
OR DEATH.
Check the vehicle's charging system for proper operation in accordance with the
Service Information.
Is the vehicle's charging system operating properly?All
Ye s!Go To 3
No!Repair the vehicle's charging system in accordance with the
Service Information.
Perform HEATER VERIFICATION TEST - VER 1.
99
CABIN HEATER