SERVICE MANUAL NUMBER 23
TROUBLE CODE DIAGNOSTICS - 454/502 MAG MPI & 8.2L MPI
90-861326--1 MARCH 1999
Page 5F-13
Code 33 (3 of 3): Manifold Absolute Pressure (MAP) Sensor Circuit (Non-Scan)
STEP
ACTION
VALUE
YES
NO
PROCEED TO
Is voltage reading over 4 volts?
–
Step 5
Step 8
5
1. Ignition OFF.
2. Connect a test light to battery positive
(B+).
3. Touch test light to harness terminal “B”
(MAP sensor signal).
Is test light on?
–
Step 6
Step 9
6
1. Disconnect ECM.
2. Touch test light connected to battery pos-
itive (B+) to harness terminal “B.” (See Note)
–
Step 11
Step12
7
Connect DVOM from MAP sensor harness ter-
minal “C” to a good ground on engine.
–
Step 14
Step 13
7
minal C to a good ground on engine.
Is voltage reading over 4 volts?
–
Ste 14
Ste 13
8
Connect DVOM between harness terminal “B”
and engine ground (–).
Is voltage reading over 4 volts?
–
Step 10
Step 15
9
MAP sensor faulty.
–
–
–
10
CKT 432 shorted to voltage.
–
–
–
11
CKT 432 shorted shorted to ground.
–
–
–
12
Faulty ECM.
–
–
–
13
Faulty connection at ECM, CKT 416 open,
shorted to ground, or faulty ECM.
–
–
–
14
Faulty connection at ECM, CKT 814 open or
faulty ECM.
–
–
–
15
Open CKT 432, faulty connection at ECM or
faulty ECM.
–
–
–
16
Repair low or unsteady vacuum problem.
–
–
–
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