
RENR5622 93
Troubleshooting Section
Table 32
Event Code
Description
Conditions wh
ich Generate this Code
System Respon
se
MID0036-CID0190-FMI08Engine
Speed signal abnormal
The engine speed is greater than z ero
rpm and the pattern from the timing ring
is incorrect for five seconds.
Theenginespeedissettozerorpm.
Thecodeisactive.
The code is logged if the pattern from
the timing ring returns for five seconds.
The
Electronic Control Module (ECM) provides the
engine speed/timing sensor with 12 ± 1.0 VDC. The
engine speed/timing sensor provides a pulse signal
to
the ECM. The signal is created as the timing
reference gear rotates past the pickup of the engine
speed/timing sensor. The timing reference gear is
mo
unted on the rear of the left camshaft. A unique
tooth pattern on the timing reference gear allows the
ECM to determine the crankshaft position, rotation,
a
nd rpm.
The engine speed/timing sensor generates a pulse
s
ignal to the ECM as each tooth passes the sensor.
The ECM counts the pulses in order to determine the
engine rpm. The ECM memorizes the pattern of the
p
ulses. The ECM compares that pattern to a standard
pattern in order to determine the crankshaft position.
The ECM uses this information to determine the No.
1 cylinder. The ECM then triggers each fuel injector to
fire in the correct firing order and at the correct time.
The actual timing and duration of each injection is
determined by the ECM. The ECM uses engine rpm
and engine load to determine the timing and duration
of injection. The loss of the signal from the engine
speed/timing sensor generates a diagnostic code.
The loss of the signal from the engine speed/timing
sensor triggers the termination of the signals to the
fuel injectors by the ECM.
Note: If the engine timing gear is installed backward,
the ECM will generate a diagnostic code. The
diagnostic code that is generated will be 190-08
Engine Speed signal abnormal. If this code is active,
the ECM will not fire the injectors.
g01208740
Illustration 34
Left side view
(1) E ngine speed/timing sensor