Mercury MerCruiser MCM 7.4L MPI User Manual

TROUBLE CODE DIAGNOSTICS - 7.4L MPI SERVICE MANUAL NUMBER 23
Page 5G-46 90-861326--1 MARCH 1999
Code 22 (2 of 3): Throttle Position (TP) Sensor Circuit (Scan) Low Signal
Voltage
TEST DESCRIPTION:
Number(s) below refer to step number(s) on the diagnostic table.
Step 2. With the throttle closed, the TP sensor voltage should read 0.3-0.9 volt. If it does
not, check the throttle cable adjustment or for bent or binding linkage.
Step 3. This test simulates a DTC 21. If the ECM recognizes the high signal voltage, the
ECM and wiring are OK.
Step 4. This test checks for the 5 volt reference on CKT 416.
STEP
ACTION VALUE YES NO
PROCEED TO
1
Was the “On-Board Diagnostic” (OBD) System
Check Performed?
– Step 2
Go to
OBD
System
Check
2 1. Throttle closed.
2. Ignition “OFF.”
Does scan tool indicate TP sensor voltage
less than the specified value?
.36 Volt Step 3 Step 5
3 1. Ignition “OFF.”
2. Disconnect TP sensor harness connec-
tor.
3. Connect a jumper wire from harness ter-
minal “A” (CKT 416) to harness terminal “B”
(CKT 417).
4. Ignition “ON,” engine “OFF.”
Does scan tool indicate TP sensor voltage
greater than the specified value?
4 Volts Step 8 Step 4
4 1. Ignition “OFF.”
2. Connect DVOM from harness terminal
“A” (CKT 416) to a known good ground.
Does scan tool indicate TP sensor voltage
greater than the specified value?
4 Volts Step 7 Step 6
5
Trouble code 22 is intermittent. Locate and
repair intermittent faulty connections. Refer to
“Diagnostic Aids”.
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Index

Mercury MerCruiser MCM 7.4L MPI Specifications

General

Brand	Mercury
Model	MerCruiser MCM 7.4L MPI
Category	Engine
Language	English