SERVICE MANUAL NUMBER 23
TROUBLE CODE DIAGNOSTICS - 454/502 MAG MPI & 8.2L MPI
90-861326--1 MARCH 1999
Page 5F-35
Code 43 (2 of 3): Knock Sensor (KS) Circuit (Scan)
STEP
ACTION
VALUE
YES
NO
PROCEED TO
1
Was the “On-Board Diagnostic” (OBD) System
Check Performed?
–
Step 2
Go to
OBD
System
Check
1. Install scan tool.
2 E
i
idli
l
t t
t
b
2
2. Engine idling, coolant temperature above
150
°
F (66
°
C).
–
150 F (66 C).
Does scan tool indicate a fixed value
greater than zero degrees of knock retard?
Step 3
Step 9
1. Reconnect 5-way KS module connector Dis-
connect knock sensor harness connector.
2. Connector a test light to battery positive bat-
tery positive (B+).
3
3. Start engine.
3
4. Hold engine speed steady at 2500 rpm.
5. Repeatedly touch test light to knock sensor
harness connector terminal (CKT 496).
Does a noticeable rpm drop occur or using
timing light, did timing drop?
–
Step 8
Step 4
1. Ignition OFF.
2. Disconnect ECM J-1 connector.
4
3. Ignition ON.
8-10
4
4. Connect a DVOM from ECM harness
connector terminal “J1-1” (CKT 485) to ground
(–).
8 10
Volts
Are 8-10 volts present?
Step 5
Step 7
1. Allow DVOM voltage to stabilize.
2. Connect a test light to battery positive (B+).
5
3. Touch test light to knock sensor connector
terminal (CKT 496).
Does voltage value change?
–
Step 14
Step 6
1. Disconnect knock module harness connec-
tor.
6
2. Connect a test light to battery positive (B+).
6
3. Touch the test light to KS harness connector
terminal “D” (CKT 486).
Is test light on?
–
Step 10
Step 13
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