Mercury MerCruiser MCM 454 Mag MPI Service Manual page 757

TROUBLE CODE DIAGNOSTICS - 7.4L MPI
Code 22 (2 of 2): Throttle Position (TP) Sensor Circuit (Non-Scan) Signal
Voltage Low
STEP
1
2
3
4
5
6
7
Index
Page 5G-12
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ACTION
Was the "On-Board Diagnostic" (OBD) System
Check Performed?
1. Marine Diagnostic Code Tool switched to the
normal mode.
2. Ignition "OFF."
3. Disconnect throttle sensor harness connec-
tor.
4. Connect a jumper wire form harness termi-
nal "A" (CKT 416) to harness terminal "C"
(CKT 417).
5. Start engine and idle for 2 minutes or until
Marine Diagnostic Code Tool indicates a
stored trouble code.
6. Ignition "ON," engine "OFF."
7. Switch Marine Diagnostic Code Tool to "Ser-
vice Mode" and note trouble code.
Is trouble code 21 present?
1. Remove jumper wire from CKT 416 and
CKT 417.
2. Connect DVOM from harness terminal "A"
(CKT 416) to harness terminal "B" (CKT 813).
Is voltage reading above the specified val-
ue?
Locate and repair intermittent faulty connec-
tions. If OK, replace faulty throttle position sen-
sor. Is action complete?
Locate and repair open or short to ground in
CKT 417. If a problem is found, repair as nec-
essary. Was a problem found?
Locate and repair open or short to ground in
CKT 416. Also check CKT 416E to the MAP
sensor for a short to ground. If a problem is
found, repair as necessary. Was a problem
found?
Repair faulty ECM connections or replace
faulty ECM. Is action complete?
SERVICE MANUAL NUMBER 23
VALUE YES NO
PROCEED TO
Go to
OBD
– Step 2
System
Check
– Step 4 Step 3
4 Volts Step 5 Step 6
Verify
–
Repair
Verify
– Step 7
Repair
– Step 7
Verify
Repair
–
90-861326--1 MARCH 1999
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