For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Instrument Cluster Schematics .
1 | Did you perform the Instrument Panel Cluster Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - Instrument Cluster
2 |

1. Start the engine.
2. Observe the transmission fluid temperature gage.

Does the transmission fluid temperature gage display that the fluid temperature is within the normal operating range?

--

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3 |

1. Turn the ignition OFF.
2. Disconnect the transmission fluid temperature gage.
3. Turn the ignition ON, with the engine OFF.
4. Connect a test lamp between the ignition 3 voltage circuit of the transmission fluid temperature gage and a good ground.

Does the test lamp illuminate?

--

Go to Step 4

Go to Step 12

4 | Connect a test lamp between the ignition 3 voltage circuit of the transmission fluid temperature gage and the ground circuit of the transmission fluid temperature gage. Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 13
5 |

1. Turn the ignition OFF.
2. Connect the transmission fluid temperature gage.
3. Disconnect the transmission fluid temperature sensor.
4. Turn the ignition ON, with the engine OFF.

Does the transmission fluid temperature gage display at or below the specified value?

40°C (104°F)

Go to Step 6

Go to Step 7

6 |

1. Turn the ignition OFF.
2. Connect a 3 ampere fused jumper between the signal circuit and the ground circuit of the transmission fluid temperature gage sensor.
3. Turn the ignition ON, with the engine OFF.

Does the transmission fluid temperature gage display at or above the specified value?

120°C (248°F)

Go to Step 10

Go to Step 8

7 | Test the signal circuit of the transmission fluid temperature sensor for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 11
8 | Test the signal circuit of the transmission fluid temperature sensor for an open, for a short to voltage, or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 9
9 | Test the ground circuit of the transmission fluid temperature sensor for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 11
10 | Inspect for poor connections at the harness connector of the transmission fluid temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15
11 | Inspect for poor connections at the harness connector of the transmission fluid temperature gage. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14
12 | Repair the open, the short to ground, or the high resistance in the ignition 3 voltage circuit of the transmission fluid temperature gage. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 16

--

13 | Repair the open, or the high resistance in the ground circuit of the transmission fluid temperature gage. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 16 | --
14 | Replace the transmission fluid temperature gage. Refer to Transmission Fluid Temperature Gage Replacement . Did you complete the replacement? | -- | Go to Step 16 | --
15 | Replace the transmission fluid temperature sensor. Refer to Transmission Fluid Temperature Sensor Replacement in Automatic Transmission - Allison. Did you complete the replacement? | -- | Go to Step 16 | --
16 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2