TROUBLE CODE DIAGNOSTICS - 7.4L MPI
SERVICE MANUAL NUMBER 23
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.
Step6.ThisstepdeterminesifCKT485isshortedtovoltageoriftheKSmoduleisfaulty.
STEP
ACTION
VALUE
YES
NO
PROCEED TO
Go to
Was the “On-Board Diagnostic” (OBD) System
Check Performed?
OBD
System
Check
1
2
–
Step 2
1.
Disconnect the 5 wire Knock sensor (KS)
module harness connector.
2.
terminal “E” (CKT496) to a known good ground
near the knock sensor.
Connect DVOM from KS module harness 3500 to
4700
Ohms
Is resistance between the specified value?
Step 3
Step 7
1.
tor.
Reconnect KS module harness connec-
3
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.
3.
Disconnect ECM J1 connector.
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
Page 5G-34
90-861326--1 MARCH 1999
| 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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