SERVICE MANUAL NUMBER 23
TROUBLE CODE DIAGNOSTICS - 7.4L MPI
Code 44 (3 of 3): Knock Sensor (KS) Circuit (Scan) - No Knock Detected
STEP
ACTION
VALUE
YES
NO
PROCEED TO
5.
Using a test light connected to battery
positive (B+), repeatedly touch knock sensor
harness terminal (CKT 496).
Does the voltage value change?
–
Step14
Step 5
1.
connector.
Disconnect KS module 5-wire harness
5
6
2.
positive (B+), probe KS module harness termi-
nal “D” (CKT 486).
Using a test light connected to battery
Does the test light illuminate?
–
Step 6
Step 9
Using a test light connected to ground, probe
KS module harness terminal “C” (CKT 485).
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.
Verify
–
–
Repair
Locate and repair open in ground CKT 486. Is
action complete?
9
–
–
–
–
10
11
Replace faulty KS module. Is action complete?
1.
Disconnect both knock sensor electrical
connectors.
2.
Using a DVOM, measure the resistance
of each sensor from the sensor terminal to
ground.
7600
8800
Ohms
to
Is the resistance of each sensor within the
specified value?
Step 15 Step 12
12
13
Replace faulty KS sensor. Is action complete?
Replace faulty KS module. Is action complete?
–
–
–
–
Repair faulty ECM connections or replace
faulty ECM. Is action complete?
Verify
Repair
14
–
–
DTC 44 is intermittent. Locate and repair inter-
mittent faulty connections. Refer to “Diagnostic
Aids.”
15
–
–
90-861326--1
MARCH 1999
Page 5G-67
| 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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