
RENR9348-01 141
Troubleshooting Section
D. Check the harness and the wiring for abrasion
and for pinch po
ints from each sensor back to the
ECM.
Expected Resu
lt:
All of the connectors, pins and sockets are completely
coupled and/o
r inserted and the harness and wiring
are free of corrosion, of abrasion, and of pinch points.
Results:
•
OK – The harness and connectors appear to be
OK. Proceed t
oTestStep4.
•
Not OK – The connectors and/or wiring are not
OK.
Repair: Repair the wiring and/or the connectors.
Replace part
s, if necessary. Ensure that all of the
seals are properly in place and ensure that the
connectors are completely coupled. Verify that the
repair elim
inates the problem.
STOP.
Test Step 4. Measure the Sensor
Resistance through the E ngine Harness
A. Disconnect
the J2/P2 ECM connectors.
B. If you are troubleshooting a problem with the
primary eng
ine speed/timing sensor, perform the
following procedure:
a. Measure th
e sensor’s resistance between
P2-25 (primary engine speed/timing +) and
P2-35 (primary engine speed/timing -).
b. Check for an intermittent open circuit or for
a short circuit by moving the harness while
youtaketh
e resistance measurement. Pull
the wires that are directly behind the sensor
or shake the wires that are directly behind the
sensor.
Resistance at 25 °C (77 °F) ... 75 to 230 Ohms
C. If you are troubleshooting a problem with the
secondary engine speed/timing sensor, perform
the follo
wing procedure:
a. Measure the sensor’s resistance between
P2-47 (s
econdary engine speed/timing +) and
P2-46 (secondary engine speed/timing -).
b. Check fo
r an intermittent open circuit or for
a short circuit by moving the harness while
you take the resistance measurement. Pull
the wire
s that are directly behind the sensor
or shake the wires that are directly behind the
sensor.
Resistance at 25 °C
(77 °F) ......................... ....... 600 to 18
00 Ohms
Expected Result:
The resistance measurement is within the
specifications.
Results:
•
OK – The resist
ance measurement is within the
specifications.
Repair: Neith
er a short circuit nor an open circuit
is indicated in the circuit. Replace the ECM. Refer
to Troubleshooting, “Replacing the ECM”.
STOP.
•
Not OK – The r ea
dings are not within the
specifications. The sensor resistance is not within
the acceptable range when the sensor resistance
is measured t
hrough the engine harness. Proceed
to Test Step 5.
Test Step 5.
Measure the Resistance of
the Sensor
A. Disconnect the harness connector for the suspect
sensor.
B. Thoroughly inspect the sensor’s connectors.
Refer to Tro
ubleshooting, “Electrical Connectors
- Inspect”.
C. Measure th
e sensor’s resistance between
terminals 1 and 2.
Resistanc
e for primary engine speed/timing
sensor at 25 °C (77 °F) ............... 75 to 230 Ohms
Resistanc
e for secondary engine speed/timing
sensor at 25 °C (77 °F) ........... 600 to 1800 Ohms
Expected R
esult:
The resistance measurement is within specifications.
Results:
•
OK – The re
ading is within the specification. There
isaproblemwiththewiringbetweentheengine
speed/timing sensor and the ECM. There may be
a problem
with a connector.
Repair: Repair the wiring and/or the connector.
Replace p
arts, if necessary. Verify that the problem
is resolved.
STOP.