Mercury MerCruiser MCM 7.4L MPI User Manual

TROUBLE CODE DIAGNOSTICS - 7.4L MPI SERVICE MANUAL NUMBER 23
Page 5G-54 90-861326--1 MARCH 1999
Code 33 (2 of 3): Manifold Absolute Pressure (MAP) Sensor Circuit (Scan)
High Signal Voltage
STEP ACTION VALUE YES NO
PROCEED TO
6
Repair low or unsteady vacuum problem. Is
action complete?
– –
7
Trouble code is intermittent. Locate and repair
intermittent faulty connections. Refer to “Diag-
nostic Aids”.
– –
8
Locate and repair short to voltage in CKT 432.
If a problem is found, repair as necessary.
Was
a problem found?
–
Verify
Step 11
9
Locate and repair open in CKT 814. If a prob-
lem is found, repair as necessary.
Was a prob-
lem found?
–
y
Repair
Step 11
10
Check for plugged or leaking sensor vacuum
fitting. If OK, replace faulty MAP sensor.
Is
action complete?
– –
11
Repair faulty ECM connections or replace
faulty ECM.
Is action complete?
– –
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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