SERVICE MANUAL NUMBER 24
DIAGNOSTICS
Code 23 (2 of 3): Intake Air Temperature (IAT) Sensor Circuit
Step
Action
Yes
No
PROCEED TO
Was the “On-Board Diagnostic” (OBD) System Check
Performed?
1.
2.
Step 2.
OBD
Are you using a Scan Tool?
Ignition ON
Step 3. Step 7.
3.
Does the scan tool display a temperature less than
Step 4. Step 5.
-22
°F (-30°C)?
a. Ignition OFF
b. Disconnect IAT harness connector.
c. Connect a jumper wire from harness terminal “A” CKT
472 to harness terminal “B” CKT 813.
4.
d. Ignition ON, engine OFF.
Does scan tool display a temperature above 266°F
Step 9. Step 6.
(130
°C)?
Trouble code 23 is intermittent. Locate and repair inter-
mittent faulty connections.
5.
6.
–
Verify
Repair
Locate and repair open in CKT 472 or CKT 813.
a. Ignition OFF.
b. Disconnect IAT sensor harness terminals.
c. Ignition ON, engine OFF.
7.
8.
4.
Connect DVOM across the sensor harness terminals.
Is voltage above 4 volts?
Step 9. Step 8.
a. Connect positive (+) DVOM lead to harness terminal “B”
CKT 472 (5 volt reference).
b. Connect negative (–) DVOM lead to a known good
ground.
Is voltage above 4 volts?
Step 11. Step 10.
–
Locate and repair intermittent faulty connections. If OK,
replace faulty IAT sensor.
9.
Locate and repair open CKT 472 or faulty ECM connec-
tions.
Verify
–
10.
11.
Repair
–
Locate and repair open ground CKT 813 or faulty ECM
connections.
Index
90-861327--1
OCTOBER 1999
Page 5G-65
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 305 CID, Mercury MerCruiser 350 CID |
| Model Year | 1998, 1999, 2000, 2001 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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