Troubleshooting

164 RENR2696-01
Troubleshooting Section
Note: The test ECM should have the same values
and the same par
ameters as the suspect ECM.
2. Remove all jumpers and replace all connectors.
3. Use the electronic service tool to recheck the
system for active diagnostic codes.
4. Repeat the test step.
5. If the problem
is resolved with the test ECM,
reconnect the suspect ECM.
6. If the problem
returns with the suspect ECM,
replace the ECM.
7. Verify that th
e repair eliminates the problem.
STOP.
Test Step 10. Bypass the Harness
Wiring Between the ECM and the Sensor
Connector.
A. Turn the key
switch to the OFF position.
B. Disconnect J1/P1 ECM connector and the sensor
connector.
C. Remove the sensor signal wire from the ECM
connector.
D. Remove the signal wire (terminal “C”) from the
sensor conn
ector on the engine harness.
E. Fabricate a jumper wire that is long enough to
reach from
the ECM to the sensor connector or
use an engine sensor harness bypass with 3
terminals.
Note: If an engine sensor harness bypass is being
made, crimp a Deutsch socket on one end in order to
connect to
the ECM. Crimp either a Deutsch pin or a
Deutsch socket on the other end, as required.
F. Insert th
e one end of the engine sensor harness
bypass into P1 ECM connector on the engine
harness. Insert the other end of the engine sensor
harness b
ypass into the sensor connector of the
engine harness.
G. Reconnec
t J1/P1 ECM engine connector and the
sensor connector.
H. Turn the
keyswitch to the ON position.
I. Use the electronic service tool to monitor the
“Active
Diagnostic Code” screen for either the
open circuit diagnostic code for the sensor or the
short circuit diagnostic code for the sensor.
Expected Result:
The diagnostic code disappears when the jumper or
the bypass is installed.
Results:
•
OK –Thereisap
roblem in the wiring harness.
Repair: Perform the following repair:
1. Repair the faulty wiring harness or replace the
faulty wiring harness.
2. Clear all diagnostic codes.
3. Use the electr
onic service tool in order to verify
that the repair eliminates the problem.
STOP.
•
Not OK – Restart this procedure and carefully
perform each
step. STOP.
i01798872
Engine Speed/Timing Sensor
Circuit-Te
st
System Operation Description:
Use thi s proc
edure to troubleshoot the system under
the following conditions:
•
There is an a
ctive diagnostic code for the engine
speed/timing sensors.
•
Use this pro
cedure if another procedure has
directed you here.
The engine u
ses two engine speed/timing sensors.
One sensor is located in the cylinder block. The
speed/timing sensor that is mounted on the cylinder
block meas
ures the crankshaft speed and the
speed/timing sensor calculates the position of the
crankshaft. In order to determine the engine rpm, the
Electroni
c Control Module (ECM) measures the time
between pulses that are created by the sensor as the
speed-timing wheel rotates.
The second speed/timing sensor is located in the fuel
injection pump. This speed/timing sensor measures
the speed
and the position of the fuel injection pump.
The ECM uses both sensor signals to calculate the
engine sp
eed and the correct engine timing.