GM Service Manual Online
For 1990-2009 cars only

Object Number: 56420  Size: LF
Engine Controls Components
DIESEL PCM, CKP, FUEL TEMP, ITS
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The fuel temperature sensor is a thermistor that controls signal voltage to the PCM. When the fuel is cold, the sensor resistance is high, therefore the PCM will see high signal voltage. As fuel warms, sensor resistance becomes less and voltage drops. The fuel temperature sensor is integrated with the optical sensor. This is a type B DTC.

Conditions for Setting the DTC

    • Fuel temperature greater than 102°C (215°F).
    • Conditions met for 2 seconds.

Action Taken When the DTC Sets

Poor idle quality during hot conditions.

Conditions for Clearing the MIL/DTC

    • The PCM will turn the MIL off after three consecutive trips without a fault condition.
    • A History DTC will clear when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle.
    • Use of a Scan Tool

Diagnostic Aids

A scan tool reads fuel temperature in degrees centigrade.

An intermittent may be caused by the following:

    • Poor connections
    • Rubbed through wire insulaton
    • Broken wire inside the insulation

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

  1. This step determines if DTC P0182 is a hard failure or an intermittent condition.

  2. This test will determine if signal circuit is shorted to ground.

Step

Action

Value(s)

Yes

No

1

Important: Before clearing DTC(s) use the scan tool Capture Info to record freeze frame and failure records for reference, as data will be lost when Clear Info function is used.

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Scan tool connected.
  2. Start the engine.
  3. Monitor the Fuel Temp display on scan tool.

Is Fuel Temp greater than the specified value?

102°C (215°F)

Go to Step 3

Go to Step 5

3

  1. Engine OFF.
  2. Ignition ON.
  3. Disconnect the Optical/Fuel Temperature sensor connector.

Is Fuel Temp less than or equal to the specified value?

17°C ( 63°F)

Go to Step 7

Go to Step 4

4

  1. Ignition OFF.
  2. Using the J 39200 measure the resistance across the Fuel Temperature sensor harness connector.

Is the resistance at the specified value?

Infinite

Go to Step 8

Go to Step 6

5

DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If additional DTCs were stored, refer to the applicable DTC table(s) first.

Are additional DTC(s) stored?

--

Go to the Applicable DTC Table

Go to Diagnostic Aids

6

Repair the short to ground in the Fuel Temp signal circuit.

Is the action complete?

--

Go to Step 9

--

7

Replace the fuel injection pump. Refer to Fuel Injection Pump Replacement .

Important: The new injection pump must be timed. Refer to Checking/Adjust Injection Timing .

Is the action complete?

--

Go to Step 9

--

8

Replace the PCM.

Important: The new PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming

Is the action complete?

--

Go to Step 9

--

9

  1. Using the Scan Tool, select DTC, Clear Info.
  2. Start engine and idle at normal operating temperature.
  3. Select DTC, Specific, then enter the DTC number which was set.
  4. Operate the vehicle until the Scan Tool indicates that the diagnostic Ran.

Does the Scan Tool indicate that the diagnostic Passed?

--

Go to Step 10

Go to Step 2

10

Using the Scan Tool, select Capture Info, Review Info.

Are any DTCs displayed that have not been diagnosed?

--

Go to the Applicable DTC Table

System OK