90-823225--1 10965E-110 - ELECTRONIC FUEL INJECTION (MULTI-PORT AND THROTTLE BODY)
Code 43: Knock Sensor (KS) (Scan)
(1 Of 2)
FUSE 15A
TO SYSTEM
RELAY
KNOCK SIGNAL
MODULE
KNOCK SENSOR
(KS) SIGNAL
CIRCUIT DESCRIPTION:
Sensing engine detonation or spark knock is accom-
plished with a module that sends a voltage signal to
the ECM. As the knock sensor detects engine knock,
the voltage from the KS module to the ECM drops,
and this signals the ECM to retard timing. The ECM
will retard the timing when knock is detected and
RPM is above a certain value.
TEST DESCRIPTION:
Number(s) below refer to circled number(s) on the
diagnostic chart.
1. This step determines if there is a problem in the
circuit. When an KS circuit fails, the ECM will
switch to a default value of about 3.2 degrees of
timing retard.
2. This step checks if there is a voltage source to the
knock sensor from the KS module.
3. This step will determine if the knock sensor is
faulty.
DIAGNOSTIC AIDS:
If CKT 496 is routed too close to secondary ignition
wires, the KS module may see the interference as a
knock signal, resulting in false retard.
An intermittent problem may be caused by a poor or
corroded connection, rubbed through wire connec-
tion, a wire that is broken inside the insulation, or a
corroded wire.
Any circuitry that is suspected as causing the inter-
mittent complaint should be thoroughly checked for
backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, corroded terminals
and/or wiring, or physical damage to the wiring har-
ness. After repairs, clear codes following “Clearing
Codes” in “ECM Self-Diagnostics.” Failure to do so
may result in codes not properly being cleared.
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