TROUBLE CODE DIAGNOSTICS - 454/502 MAG MPI & 8.2L MPI
SERVICE MANUAL NUMBER 23
Code 21 (2 of 2): Throttle Position (TP) Sensor Circuit (Non-Scan)
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. Ignition OFF.
2.
Disconnect throttle position sensor har-
ness connector.
3.
4.
Ignition ON.
Connect DVOM from harness terminal
“A” (5 volt reference to harness terminal “B”
(sensor ground).
Is voltage reading over 4 volts?
–
–
Step 3
Step 4
Step 6
Step 5
Connect DVOM from harness terminal “A”
(CKT 416) to harness terminal “C” (throttle
position sensor signal, CKT 417).
3
4
Is voltage reading over 4 volts?
1. Ignition OFF.
2.
Connect a test light to battery positive
(B+).
3.
throttle position sensor signal).
Touch test light to harness terminal “C”
(
–
–
Step 7 Step 10
Is test light on?
Connect DVOM between harness terminal “C”
and engine ground (–).
5
Step 8
Step 9
Is voltage over 4 volts?
Connect DVOM from throttle position sensor
harness terminal “A” to a good ground on
engine.
6
7
–
Step 14 Step 13
Is voltage over 4 volts?
1. Disconnect ECM.
2.
throttle position sensor signal).
Touch test light to harness terminal “C”
(
–
Step 11 Step 12
Is test light on?
8
9
Check for CKT 417 shorted to voltage.
–
–
–
–
–
–
Open or CKT 417, faulty connection at ECM or
faulty ECM.
10
11
12
Throttle position sensor faulty.
Check for CKT 417 shorted to ground.
Faulty ECM.
–
–
–
–
–
–
–
–
–
Faulty connection at ECM, CKT 416, shorted
to ground or faulty ECM.
13
14
–
–
–
–
–
–
Faulty connection at ECM, CKT 813 open or
faulty ECM.
Index
Page 5F-8
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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