TROUBLE CODE DIAGNOSTICS - 7.4L MPI
SERVICE MANUAL NUMBER 23
Page 5G-34
90-861326--1 MARCH 1999
Code 44 (2 of 3): Knock Sensor (KS) Circuit (Non-Scan) - No Knock Detected
TEST DESCRIPTION: (CONTINUED)
Step 5. This step checks the ground circuit from the KS module. If the test light is dim,
check ground CKT 486 for excessive resistance.
Step 6. This step determines if CKT 485 is shorted to voltage or if the KS module is faulty.
STEP
ACTION
VALUE
YES
NO
PROCEED TO
1
Was the “On-Board Diagnostic” (OBD) System
Check Performed?
–
Step 2
Go to
OBD
System
Check
2
1. Disconnect the 5 wire Knock sensor (KS)
module harness connector.
2. Connect DVOM from KS module harness
terminal “E” (CKT496) to a known good ground
near the knock sensor.
3500 to
4700
Ohms
Is resistance between the specified value?
Step 3
Step 7
3
1. Reconnect KS module harness connec-
tor.
2. Disconnect knock sensor harness con-
nector.
3. Start engine.
4. Hold engine speed steady above 2500
RPM.
5. Using a test light connected to battery
positive (B+), repeated touch knock sensor
harness terminal (CKT 496).
Does the RPM drop occur, or using a timing
light, does the timing retard?
–
Step 8
Step 4
4
1. Ignition “OFF”.
2. Disconnect ECM J1 connector.
3. Connect DVOM from ECM harness ter-
minal J1-1 (CKT485) to a known good ground.
It should be 8-10 volts.
4. Allow voltage to stabilize.
5. Using a test light connected to battery
positive (B+), repeatedly touch knock sensor
harness terminal (CKT 496).
Does the voltage value change?
–
Step 14
Step 5
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