TROUBLE CODE DIAGNOSTICS - 7.4L MPI SERVICE MANUAL NUMBER 23
Page 5G-64 90-861326--1 MARCH 1999
Code 43 (2 of 2): Knock Sensor (KS) Circuit (Scan) - Continuous Knock
Detected
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 5-wire knock sensor (KS)
module harness connector
2. Ignition “ON,” engine “OFF.”
3. Using a test light connected to ground,
probe KS module harness terminal “B” (CKT
439).
Does test light illuminate?
– Step 3 Step 5
3
Using a test light connected to battery positive
(B+), probe KS module harness terminal “D”
(CKT 486).
Does test light illuminate?
– Step 4 Step 6
4 1. Ignition “OFF.”
2. Reconnect KS module harness connec-
tor.
3. Disconnect J1 connector.
8-10
4. Ignition “ON,” engine “OFF.”
Volts
5. Connect DVOM from ECM harness ter-
minal J1-1 (CKT 485) to a known good ground.
Is the voltage within the specified value?
Step 9 Step 7
5
Locate and repair open or short to ground in
CKT 439.
Is action complete?
– –
6
Locate and repair open in CKT 486.
Is action
complete?
– –
7
Locate and repair open or short to ground in
CKT 485. If a problem is found, repair as nec-
essary.
Was a problem found?
–
Verify
Repair
Step 8
8 Replace faulty KS module.
Is action complete?
– –
9
Repair faulty ECM connections or replace
faulty ECM.
Is action complete?
– –
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