engine coolant MERCEDES-BENZ SPRINTER 2006 Owner's Manual

3.2.2 ECM OPERATING MODES
As input signals to the ECM change, the ECM
adjusts its response to the output devices. For
example, the ECM must calculate a different fuel
quantity and fuel timing for engine idle condition
than it would for a wide open throttle condition.
There are several different modes of operation that
determine how the ECM responds to the various
input signals.
Ignition Switch On (Engine Off)
When the ignition is turned on the ECM activates
the glow plug relay for a time period that is deter-
mined by engine coolant temperature, intake air
temperature and battery voltage.
Engine Start-Up Mode
The ECM uses the intake air temperature sensor,
engine temperature sensor and the crankshaft po-
sition sensor (engine speed) inputs to determine
fuel injection quantity.
Normal Driving Modes
Engine idle, warm-up, acceleration, deceleration
and wide open throttle modes are controlled based
on all of the sensor inputs to the ECM. The ECM
uses these sensor inputs to adjust fuel quantity and
fuel injector timing. EGR valve control is performed
using feedback from the oxygen sensor. An oxygen
sensor is located in the exhaust manifold to sample
oxygen content exiting the engine cylinders. The
ECM uses the O2 sensor, along with other sensor
inputs, to govern the amount of exhaust gas recir-
culation to reduce HC (HydroCarbons) and CO
(Carbon Monoxide). Engine coolant is routed
through the base of the EGR valve to provide
additional cooling of the exhaust gas, which further
helps the reductions of emissions. The EGR valve
has a self-cleaning function. When the engine is
shut off, the EGR valve rotates twice to reduce
carbon deposits at the valve seat.
Overheat Production Mode
If the engine temperature is above 105ÉC (221ÉF)
and vehicle speed is above 40 km/h (25 MPH) the
ECM will limit fuel quantity for engine protection.
Limp-In Mode
The ECM utilizes different degrees of engine
limp-in. The ECM is able to limit engine rpm,
engine power output (turbo boost reduction), acti-
vate engine cooling fan or all of these functions
based on the type of fault that is detected. Critical
engine performance faults such as accelerator pedal
position sensor fault will result in a fixed idle speed
of approximately 680 rpm regardless of actual pedalposition. Other less critical faults will result in
power reduction throughout the full range of driv-
ing conditions.
Overspeed Detection Mode
If the ECM detects engine RPM that exceeds
5200 RPM, the ECM will set a DTC in memory,
limit engine RPM to no more than 2500 RPM, and
illuminate the MIL until the DTC is cleared.
After-Run Mode
The ECM transfers RAM information to ROM
and performs an Input/Output state check.
3.2.3 MONITORED CIRCUITS
The ECM is able to monitor and identify most
driveability related trouble conditions. Some cir-
cuits are directly monitored through ECM feedback
circuitry. In addition, the ECM monitors the voltage
state of some circuits and compares those states
with expected values. Other systems are monitored
indirectly when the ECM conducts a rationality test
to identify problems.
Although most subsystems of the engine control
module are either directly or indirectly monitored,
there may be occasions when diagnostic trouble
codes are not immediately identified. For a trouble
code to set, a specific set of conditions must occur
and unless these conditions occur, a DTC will not
set.
3.2.4 SKREEM OVERVIEW
The sentry key remote entry module system
(SKREEM) is designed to prevent unauthorized
vehicle operation. The system consists of a sentry
key remote entry module (SKREEM), ignition
key(s) equipped with a transponder chip and the
ECM. When the ignition switch is turned on, the
SKREEM interrogates the ignition key. If the igni-
tion key is Valid or Invalid, the SKREEM sends a
message to the ECM indicating ignition key status.
Upon receiving this message the ECM will termi-
nate engine operation or allow the engine to con-
tinue to operate.
3.2.5 SKREEM ON-BOARD DIAGNOSTICS
The SKREEM has been programmed to transmit
and monitor many different coded messages as well
as CAN Bus messages. This monitoring is called
On-Board Diagnostics. Certain criteria must be met
for a DTC to be entered into SKREEM memory. The
criteria may be a range of; input voltage, CAN Bus
message or coded messages to the SKREEM. If all
the criteria for monitoring a circuit or function are
met and a fault is detected, a DTC will be stored in
the SKREEM memory and the START ERROR indi-
cator will be turned on in the instrument cluster.
2
GENERAL INFORMATION

ecm internal error 3
ecm internal error 4
ecm internal error 4
ecm internal error 5
ecm internal fault
ecm invalid coding
ecm invalid data
ecm read error
ecm read/write error
ecm supply voltage too low
ecm voltage supply is too high
ecm voltage supply is too low
ecm write error
egr flow rate is too high
egr flow rate is too low
egr valve excessive current
egr valve signal circuit open circuit
egr valve signal circuit shorted to ground
egr valve signal circuit shorted to ground
egr valve signal circuit shorted to voltage
engine control relay plausibility
engine control relay shuts off too early
engine control relay shuts off too late
engine coolant temp sensor circuit plausibility
engine coolant temp sensor circuit plausibility
engine coolant temp sensor circuit plausibility with
engine oil sensor
engine coolant temp sensor circuit signal voltage too
high
engine coolant temp sensor circuit signal voltage too
high
engine coolant temp sensor circuit signal voltage too
low
engine coolant temp sensor circuit signal voltage too
low
*engine cranks but will not start
engine oil sensor circuit invalid level
engine oil sensor circuit level out of range
engine oil sensor circuit level out of range
engine oil sensor monitoring error
engine oil sensor oil temperature plausibility
engine oil sensor open circuit
engine oil sensor poor oil quality
engine oil sensor quality measurement error
engine oil sensor quality plausibility
engine oil sensor signal error
engine oil sensor signal plausibility
engine oil sensor signal voltage is too high
engine oil sensor signal voltage is too low
engine oil sensor synchronization error
engine oil sensor water contamination
*engine will not crank
esm can message missing or incorrect
etc can message missing or incorrect
fuel injector 1 read too large
fuel injector 1 read too large
fuel injector 1 read too small
fuel injector 1 read too smallfuel injector 2 read too large
fuel injector 2 read too large
fuel injector 2 read too small
fuel injector 2 read too small
fuel injector 3 read too large
fuel injector 3 read too large
fuel injector 3 read too small
fuel injector 3 read too small
fuel injector 4 read too large
fuel injector 4 read too large
fuel injector 4 read too small
fuel injector 4 read too small
fuel injector 5 read too large
fuel injector 5 read too large
fuel injector 5 read too small
fuel injector 5 read too small
fuel press sensor circuit malf signal voltage too high
fuel press sensor circuit malf signal voltage too low
fuel press solenoid signal plausibility high
fuel press solenoid signal plausibility low
fuel pressure sensor circuit signal voltage too high
fuel pressure sensor circuit signal voltage too low
fuel pressure solenoid circuit excessive current
fuel pressure solenoid circuit open circuit
fuel pressure solenoid circuit shorted to ground or
b+
fuel pump relay circuit open circuit
fuel pump relay circuit shorted to ground
fuel pump relay circuit shorted to voltage
fuel pump relay excessive current
fuel quantity solenoid ecm thermal overload
fuel quantity solenoid open circuit
fuel quantity solenoid short to ground
fuel quantity solenoid short to ground
fuel quantity solenoid short to voltage
fuel rail pressure malfunction deceleration error
fuel rail pressure malfunction deceleration error
fuel rail pressure malfunction fuel flow below min-
imum quantity
fuel rail pressure malfunction maximum fuel flow
exceeded
fuel rail pressure malfunction maximum fuel pres-
sure exceeded
fuel rail pressure malfunction maximum fuel pres-
sure exceeded
fuel rail pressure malfunction maximum fuel pres-
sure exceeded
fuel rail pressure malfunction plausibility with fuel
pressure solenoid
fuel rail pressure malfunction rail pressure is too
high
fuel rail pressure malfunction rail pressure is too
low
fuel rail pressure malfunction rail pressure is too
low
fuel rail pressure malfunction rail pressure is too
low
fuel rail pressure malfunction rail pressure too high
5
GENERAL INFORMATION

ohmmeter
voltmeter
jumper wires and probes
oscilloscope
6.0 GLOSSARY OF TERMS
A/Cair conditioning
APPaccelerator pedal position (sensor)
BCMbody control module
BPboost pressure (sensor)
CKPcrankshaft position (sensor)
CMPcamshaft position (sensor)
CTMcentral timer module
DLCdata link connector
ECMengine control module
ECTengine coolant temperature (sensor)
EGRexhaust gas recirculation (solenoid/
valve)
EOSengine oil sensor
IATintake air temperature (sensor)
IPintake pressure sensorMAFmass air flow (sensor)
MILmalfunction indicator lamp
msmillisecond(s)
O2oxygen sensor
PDCpower distribution center
S/Cspeed control
SKREEMsentry key remote entry module
SRCsignal range check
WIFwater in fuel (sensor)
10
GENERAL INFORMATION

Symptom List:
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT PLAUSIBILITY
P2012-ENGINE COOLANT TEMP SENSOR CIRCUIT PLAUSIBILITY
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P0115-ENGINE COOLANT TEMP
SENSOR CIRCUIT PLAUSIBILITY.
POSSIBLE CAUSES
ECT SENSOR
ECT SENSOR - COLD
ECT SENSOR - HOT
HGH RESISTANCE IN ECT SENSOR CIRCUITS
ENGINE COLD TOO LONG
TEST ACTION APPLICABILITY
1Note: The best way to diagnose this DTC is to allow the vehicle to remain
outside overnight in order to have a completely cold soaked engine.
Note: Extremely cold outside ambient temperatures may cause this DTC to
set.
Verify that the coolant level is correct.
Start the engine.
With the DRBIIIt, set the engine RPM to 1500 and allow the engine to warm up for
10-15 minutes.
With the DRBIIIt, monitor the Engine Coolant Temperature value during the warm
up cycle. Make sure the transition of temperature change is smooth.
Did the engine temperature reach a minimum of 80É C (176É F)?All
Ye s!Go To 2
No!Refer to the Service Information for cooling system performance
diagnosis. The most probable cause is a Thermostat problem.
Also, refer to any related TSBs.
Perform ROAD TEST VERIFICATION - VER-2.
2NOTE: The engine temperature must be below 50ÉC (120ÉF) for this test.
NOTE: The thermostat must be operating correctly for this test to be valid.
With the DRBIIItin Sensors, read and note the engine coolant temperature.
Using a temperature probe, measure the engine block temperature near the ECT
Sensor.
Are the readings within 7ÉC (13ÉF) of each other?All
Ye s!Go To 3
No!Go To 4
40
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
3NOTE: The thermostat must be operating correctly for this test to be valid.
Start the engine and bring the engine to operating temperature (thermostat open).
Turn the engine off and wait 10 minutes to allow the engine temperature to stabilize.
Using a temperature probe, measure the engine block temperature near the ECT
Sensor.
With the DRBIIIt, select Engine, then Sensors and read the engine coolant
temperature.
Are the readings within 7ÉC (13ÉF) of each other?All
Ye s!Test Complete.
No!Go To 4
4 Disconnect the ECT harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the ECT Sensor Signal circuit between the ECM harness
connector and the ECT harness connector.
Measure the resistance of the Sensor Ground circuit between the ECM harness
connector and the ECT harness connector.
Is the resistance below 10.0 ohms for each measurement?All
Ye s!Replace the Engine Coolant Temperature Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair the ECT Sensor circuit(s) that measured above 10.0 ohms
for high resistance.
Perform ROAD TEST VERIFICATION - VER-2.
41
DRIVEABILITY - DIESEL
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT PLAUSIBILITY Ð
Continued

Symptom:
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT PLAUSIBILITY
WITH ENGINE OIL SENSOR
When Monitored and Set Condition:
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT PLAUSIBILITY WITH EN-
GINE OIL SENSOR
When Monitored: With the engine running.
Set Condition: The ECT Sensor signal indicates a different engine temperature than the
EOS Sensor.
POSSIBLE CAUSES
CURRENT DTC
ECT SENSOR
ECT SENSOR - COLD
ECT SENSOR - HOT
ENGINE OIL SENSOR SENSOR
HGH RESISTANCE IN ECT SENSOR CIRCUITS
ENGINE COLD TOO LONG
TEST ACTION APPLICABILITY
1 Verify that the coolant level is correct.
Start the engine.
NOTE: The thermostat must be operating correctly for this test to be valid.
With the DRBIIIt, erase ECM DTCs.
With the DRBIIIt, set the engine RPM to 1500 and allow the engine to warm up for
10-15 minutes.
With the DRBIIIt, monitor the Engine Coolant Temperature value during the warm
up cycle. Make sure the transition of temperature change is smooth.
Did the engine temperature reach a minimum of 80É C (176É F)?All
Ye s!Go To 2
No!Refer to the Service Information for cooling system performance
diagnosis. The most probable cause is a Thermostat problem.
Also, refer to any related TSBs.
Perform ROAD TEST VERIFICATION - VER-2.
2 Turn the ignition on.
With the DRBIIIt, read the ECM DTCs.
Did this DTC return after performing the previous test?All
Ye s!Go To 3
No!Check for possible connecor or wiring problems at the ECT sensor
that may cause an intermittent problem. Repair as necessary.
Test Complete.
Perform ROAD TEST VERIFICATION - VER-2.
42
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
3NOTE: The engine temperature must be below 50ÉC (120ÉF) for this test.
NOTE: The thermostat must be operating correctly for this test to be valid.
With the DRBIIItin Sensors, read and note the engine coolant temperature.
Using a temperature probe, measure the engine block temperature near the ECT
Sensor.
Are the readings within 7ÉC (13ÉF) of each other?All
Ye s!Go To 4
No!Go To 5
4NOTE: The thermostat must be operating correctly for this test to be valid.
Start the engine and bring the engine to operating temperature (thermostat open).
Turn the engine off and wait 10 minutes to allow the engine temperature to stabilize.
Using a temperature probe, measure the engine block temperature near the ECT
Sensor.
With the DRBIIIt, select Engine, then Sensors and read the engine coolant
temperature.
Are the readings within 7ÉC (13ÉF) of each other?All
Ye s!Replace the Engine Oil Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 5
5 Disconnect the ECT harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the ECT Sensor Signal circuit between the ECM harness
connector and the ECT harness connector.
Measure the resistance of the Sensor Ground circuit between the ECM harness
connector and the ECT harness connector.
Is the resistance below 10.0 ohms for each measurement?All
Ye s!Replace the Engine Coolant Temperature Sensor.
Perform ROAD TEST VERIFICATION - VER-2.
No!Repair the ECT Sensor circuit(s) that measured above 10.0 ohms
for high resistance.
Perform ROAD TEST VERIFICATION - VER-2.
43
DRIVEABILITY - DIESEL
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT PLAUSIBILITY
WITH ENGINE OIL SENSOR Ð
Continued

Symptom List:
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLT-
AGE TOO HIGH
P2054-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLT-
AGE TOO HIGH
P2054-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLT-
AGE TOO LOW
Test Note: All symptoms listed above are diagnosed using the same tests.
The title for the tests will be P0115-ENGINE COOLANT TEMP
SENSOR CIRCUIT SIGNAL VOLTAGE TOO HIGH.
When Monitored and Set Condition:
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO
HIGH
When Monitored: With the ignition on.
Set Condition: The Engine Coolant Temperature Sensor Signal voltage is above 4.98 volts
for more than 3 seconds.
P2054-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO
HIGH
When Monitored: With the ignition on.
Set Condition: The Engine Coolant Temperature Sensor Signal voltage is above 4.98 volts
for more than 3 seconds.
P2054-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLTAGE TOO
LOW
When Monitored: With the ignition on.
Set Condition:
POSSIBLE CAUSES
INTERMITTENT CONDITION
ECM ECT SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE
ECT SENSOR GROUND CIRCUIT OPEN
ECT SENSOR
ECT SENSOR SIGNAL CIRCUIT OPEN
ENGINE CONTROL MODULE
44
DRIVEABILITY - DIESEL

TEST ACTION APPLICABILITY
1NOTE: If multiple DTCs are present, the most likely cause is a 5-Volt Supply
or Sensor Ground circuit shorted to voltage or ground. Refer to the Service
Information Wiring section for circuits that would affect multiple DTCs.
NOTE: If the ECM detects and stores a DTC, the ECM also stores the
engine/vehicle operating conditions under which the DTC was set. Some of
these conditions are displayed on the DRB at the same time the DTC is
displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to
duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the DRB, monitor the Engine Coolant Temperature (ECT) Sensor voltage.
Is the ECT Sensor voltage above 4.90 volts?All
Ye s!Go To 2
No!Go To 7
2 Turn the ignition off.
Disconnect the ECT Sensor harness connector.
Turn the ignition on.
Measure the voltage on the ECT Sensor Signal circuit.
Is the voltage above 5.5 volts?All
Ye s!Repair the ECT Sensor Signal circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 3
3 Turn the ignition off.
Disconnect the ECT Sensor harness connector.
Connect a jumper wire between the ECT Sensor harness connector cavities.
Turn the ignition on.
With the DRB, read the ECT Sensor voltage.
Is the voltage below 1.0 volt?All
Ye s!Replace the ECT Sensor in accordance with the Service Informa-
tion.
Perform ROAD TEST VERIFICATION - VER-2.
No!Go To 4
4 Turn the ignition off.
Disconnect the ECT Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of the ECT Sensor Ground circuit.
Is the resistance below 10.0 ohms?All
Ye s!Go To 5
No!Repair the ECT Sensor Ground circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
5 Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the ECT Sensor harness connector.
Measure the resistance of the ECT Sensor Signal circuit.
Is the resistance below 10.0 ohms?All
Ye s!Go To 6
No!Repair the ECT Sensor Signal circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
45
DRIVEABILITY - DIESEL
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLTAGE
TOO HIGH Ð
Continued

TEST ACTION APPLICABILITY
6 If there are no possible causes remaining, view repair. All
Repair
Replace and program the Engine Control Module in accordance
with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
7WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DTC When Monitored and Set Conditions. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s!Repair as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
No!Test Complete.
46
DRIVEABILITY - DIESEL
P0115-ENGINE COOLANT TEMP SENSOR CIRCUIT SIGNAL VOLTAGE
TOO HIGH Ð
Continued