SERVICE MANUAL NUMBER 23
TROUBLE CODE DIAGNOSTICS - 7.4L MPI
Code 44 (3 of 3): Knock Sensor (KS) Circuit (Non-Scan) - No Knock Detected
STEP
ACTION
VALUE
YES
NO
PROCEED TO
1.
connector.
Disconnect KS module 5-wire harness
5
2.
Using a test light connected to battery
positive (B+), probe KS module harness termi-
nal “D” (CKT 486).
Does test light illuminate?
–
Step 6
Step 9
Using a test light connected to ground, probe
KS module harness terminal “C” (CKT 485).
6
Does test light illuminate?
Step 10 Step 13
Step 11
Locate and repair open or short to ground in
CKT 496. If a problem is found, repair as nec-
essary. Was a problem found?
7
8
–
–
Inspect knock sensor terminal contacts. Also
check for abnormal mechanical engine noises.
If OK, replace faulty knock sensor. Is action
complete?
Verify
–
Repair
Locate and repair open in ground CKT 486. Is
action complete?
9
–
–
–
–
10
Replace faulty KS module. Is action complete?
1.
Disconnect both knock sensor electrical
connectors.
7600
8800
Ohms
to
2.
Using a DVOM, measure the resistance
11
of each sensor from the sensor terminal to
ground. Is the resistance of each sensor within
the specified value?
Step 15 Step 12
–
Replace faulty knock sensor. Is action com-
plete?
12
13
14
–
–
–
Replace faulty KS module. Is action complete?
–
Verify
Repair
Repair faulty ECM connections or replace
faulty ECM. Is action complete?
–
Trouble code is intermittent. Locate and repair
intermittent faulty connections. Refer to “Diag-
nostic Aids.”
15
–
–
90-861326--1
MARCH 1999
Page 5G-35
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1998, 1999, 2000, 2001 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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