TROUBLE CODE DIAGNOSTICS - 454/502 MAG MPI & 8.2L MPI
SERVICE MANUAL NUMBER 23
Code 23 (2 of 2): Intake Air Temperature (IAT) Sensor Circuit (Non-Scan)
STEP
ACTION
VALUE
YES
NO
PROCEED TO
Go to
Was the “On-Board Diagnostic” (OBD) System
Check Performed?
OBD
System
1
–
Step 2
Check
1.
2.
Disconnect IAT sensor.
Ignition ON, Engine OFF.
Greater
Than 4
Volts
Step 3
Step 5
–
–
2
Less
Than 4
Volts
3.
IAT sensor harness terminals.
Using a DVOM, check voltage between
Check resistance across IAT sensor terminals.
It should be less than 25,000 Ohms, refer to
table for approximate temperature to resis-
tance values. Is it Less Than 25,000 Ohms?
3
4
–
Step 4
Step 8
Check for signal circuit shorted to voltage. If
not shorted to voltage, code 23 is intermittent.
–
–
–
–
Greater
Than 4
Volts
Step 6
Check for voltage between harness connector
signal circuit and ground.
5
6
Less
Than 4
Volts
Step 7
–
–
–
Faulty sensor ground circuit, faulty connec-
tions, or faulty ECM.
–
Open signal circuit, faulty connection, or faulty
ECM.
7
8
–
–
–
–
–
–
Replace sensor.
IAT Sensor
Temperature - to - Resistance Values (Approximate)
°
F
°C
OHMS
210
160
100
70
40
20
100
70
38
20
4
-7
-18
-40
185
450
1,800
3,400
7,500
13,500
25,000
100,700
0
-40
Index
Page 5F-10
90-861326--1 MARCH 1999
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1998, 1999, 2000, 2001 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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Marine readers have rated Mercury MerCruiser GM V8 GM V8 454 CID 7.4L and 502 cid 8.2L Marine Engines Service Manual Number 23 5.0 out of 5.0 based on 1 product reviews. Just need the manual. Wrote review. Can't technically review what I haven't seen yet...