Test Procedure

DA1: CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)
- Are any of the following DTCs present during PCM or transmission control module (TCM) self-test: P0112, P0113, or P0114?
- Yes: For KOEO and KOER DTC P0112, GO to DA6.
  For KOEO and KOER DTC P0113, GO to DA2.
  
  For all others, GO to DA8.
- No: Unable to duplicate or identify the concern at this time.
  RETURN to SYMPTOM CHARTS for further direction.

DA2: DTC P0113: CHECK THE IAT SIGNAL CIRCUIT

The DTC indicates the sensor signal is greater than the self-test maximum.
MAF/IAT Sensor connector disconnected.
Key ON, engine OFF.

Measure the voltage between:

(+) MAF/IAT Sensor Connector, Harness Side	(-)
IAT - Pin 1	Ground

Is the voltage between 4.5 - 5.5 V?

Yes: GO to DA3.
No: GO to DA4.

DA3: CHECK IAT SENSOR RESISTANCE

Key in OFF position.

Measure the resistance between:

(+) MAF/IAT Sensor Connector, Component Side	(-) MAF/IAT Sensor Connector, Component Side
IAT - Pin 1	SIGRTN - Pin 2

Is the resistance between 1K - 500K ohms?

Yes: GO to DA4.
No: INSTALL a new MAF/IAT sensor.
REFER to the ELECTRONIC ENGINE CONTROLS .

CLEAR the DTCs. REPEAT the self-test.

DA4: CHECK THE SIGNAL AND SIGRTN CIRCUITS FOR AN OPEN IN THE HARNESS

PCM connector disconnected.

Measure the resistance between:

(+) MAF/IAT Sensor Connector, Harness Side	(-) PCM Connector, Harness Side
IAT - Pin 1	IAT - Pin B39
SIGRTN - Pin 2	SIGRTN - Pin B41

Are the resistances less than 5 ohms?

Yes: GO to DA5.
No: REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test.

DA5: CHECK THE SIGNAL FOR A SHORT TO VOLTAGE IN HARNESS

Key in OFF position. PCM connector disconnected.
Key ON, engine OFF.

Measure the voltage between:

(+) MAF/IAT Sensor Connector, Harness Side	(-)
IAT - Pin 1	Ground

Is the voltage greater than 1 V?

Yes: REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test.
No: GO to DA11.

DA6: DTC P0112: SIMULATE AN OPPOSITE SIGNAL TO THE PCM
NOTE: The DTC indicates the sensor signal is less than the self-test minimum.
- MAF/IAT Sensor connector disconnected.
- Key ON, engine OFF.
- Access the PCM and monitor the IAT PID.
- Is the voltage greater than 4.2 V?
- Yes: INSTALL a new MAF/IAT sensor.
  REFER to the ELECTRONIC ENGINE CONTROLS .
  
  CLEAR the DTCs. REPEAT the self-test.
- No: Key in OFF position.
  GO to DA7.

DA7: CHECK THE SENSOR SIGNAL FOR A SHORT TO GROUND

PCM connector disconnected.

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) PCM Connector, Harness Side
IAT - Pin B39	SIGRTN - Pin B41

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) Vehicle Battery
IAT - Pin B39	Negative terminal

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) PCM Connector, Harness Side
IAT - Pin B39	MAF RTN - Pin B43

Is the resistance greater than 10K ohms?

Yes: GO to DA11.
No: REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test.

DA8: SELF-TEST DTCS P0112, P0113, P0114 OR P1112: INTERMITTENT CHECK
- Key ON, engine OFF.
- Access the PCM and monitor the IAT PID.
- While observing the PID, carry out the following:
  - Tap on the sensor to simulate road shock
  - Wiggle the sensor connector
- Is there a large change in the voltage reading?
- Yes: DISCONNECT and INSPECT the connector.
  If OK, INSTALL a new MAF/IAT sensor.
  
  REFER to the ELECTRONIC ENGINE CONTROLS .
  
  CLEAR the DTCs. REPEAT the self-test.
- No: GO to DA9.
DA9: CHECK THE WIRING HARNESS
- Access the PCM and monitor the IAT PID.
- While observing the PID, wiggle, shake, and bend small sections of the wiring harness working from the sensor to the PCM.
- Is there a large change in the voltage reading?
- Yes: ISOLATE the concern.
  REPAIR as necessary.
  
  CLEAR the DTCs. REPEAT the self-test.
- No: GO to DA10.
DA10: CHECK THE PCM AND VEHICLE HARNESS CONNECTORS
- PCM connector disconnected.
- MAF/IAT Sensor connector disconnected.
- Are the connectors and pins OK?
- Yes: DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .
- No: REPAIR as necessary.
  CLEAR the DTCs. REPEAT the self-test.
DA11: CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Visually inspect for:
  - pushed out pins
  - corrosion
- Connect all the PCM connectors and make sure they seat correctly.
- Carry out the PCM self-test and verify the concern is still present.
- Is the concern still present?
- Yes: INSTALL a new PCM.
  REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .
- No: The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.