1.0 INTRODUCTION
The procedures contained in this manual include
all specifications, instructions and graphics needed
to diagnose engine control module (ECM) and sen-
try key remote entry module (SKREEM) problems;
they are no start, diagnostic trouble code (DTC) and
no trouble code problems for the ECM. The diagnos-
tics in this manual are based on the trouble condi-
tion or symptom being present at the time of diag-
nosis.
When repairs are required, refer to the appropri-
ate service information for the proper removal and
repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added; carryover sys-
tems may be enhanced. IT IS RECOMMENDED
THAT YOU REVIEW THE ENTIRE MANUAL TO
BECOME FAMILIAR WITH ALL NEW AND
CHANGED DIAGNOSTIC PROCEDURES.
This manual will cover all the necessary require-
ments to begin a logical diagnostic path for each
problem. If there is a diagnostic trouble code (DTC)
detected, go to the trouble code test. If there are no
DTCs present, go to a no trouble code (*), symptom
based test.
This book reflects many suggested changes from
readers of past issues. After using this book, if you
have any comments or recommendations, please fill
out the form at the back of the book and mail it back
to us.
1.1 SYSTEM COVERAGE
This diagnostic procedures manual covers 2005
Sprinter vehicles equipped with the 2.7L common
rail diesel engine.
1.2 SIX-STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the engine control module (ECM)
and sentry key immobilizer system (SKREEM) is
done in six basic steps:
²verification of complaint
²verification of any related symptom
²symptom analysis
²problem isolation
²repair of isolated problem
²verification of proper operation
NOTE: All tests in this manual should be per-
formed with the engine at operating temperature,
unless otherwise specified within a particular test.
2.0 IDENTIFICATION OF
SYSTEM
The ECM is located to the left of the steering
column behind the steering column opening cover.
The sentry remote entry module (SKREEM) is
attached to the rear of the instrument cluster.
3.0 SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
3.1 GENERAL DESCRIPTION
The 2.7L direct injection diesel engine system is
equipped with the latest technical advances. The
on-board diagnostics incorporated in the engine
control module and SKREEM are intended to assist
the field technician in repairing vehicle problems by
the quickest means.
The engine system incorporates a common rail
fuel delivery design with exhaust emission feed-
back. This design utilizes electronically controlled
solenoid valve type fuel injectors. Each injector is
controlled individually by the ECM. Injector timing
and fuel quantity are controlled by the ECM based
on inputs from various sensors. The precision con-
trol of the injectors by the ECM helps to reduce the
engine noise, odor and smoke.
3.2 FUNCTIONAL OPERATION
3.2.1 ECM ON-BOARD DIAGNOSTICS
The ECM is programmed to monitor different
circuits of the diesel fuel injection system. This
monitoring is called on-board diagnostics.
Certain criteria must be met for a diagnostic
trouble code to be entered into the ECM memory.
The criteria may be a range of: engine rpm, engine
temperature, time or other input signals to the
ECM. If all of the criteria for monitoring a system or
circuit are met, and a problem is sensed, then a
DTC will be stored in the ECM memory.
It is possible that a DTC for a monitored circuit
may not be entered into the ECM memory, even
though a malfunction has occurred. This may hap-
pen when the monitoring criteria have not been
met.
The ECM compares input signal voltages from
each input device with specifications (the estab-
lished high and low limits of the input range) that
are programmed into it for that device. If the input
voltage is not within the specifications and other
trouble code criteria are met, a DTC will be stored
in the ECM memory.
1
GENERAL INFORMATION
