For 1990-2009 cars

Refer to

#### IAC Valve, Generator, TR, Oil, and Coolant Switches

Engine Controls Components
Information Sensors/Switches Description
VSS and Cruise Control
Oxygen Sensors
OBDII Symbol Description Notice
Handling Electrostatic Discharge Sensitive Parts Notice
.

### Diagnostic Aids

For diagnosis of the instrument panel, perform the Instrument Cluster System Check in Instrument Panel, Gauges and Console.

Check for the following conditions:

• | Poor connection at PCM or Coolant Level Indicator. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

• | Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM and turn the ignition ON. Observe a voltmeter connected to the affected PCM circuit while moving connectors and wiring harnesses related to the PCM circuit. A change in voltage will indicate the location of the fault.

### Test Description

The numbers below refer to the step numbers on the Diagnostic Table:

1. Refer to IPC Microprocessor for further diagnostics. This diagnostic only covers inputs to the PCM.

2. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed. Refer to PCM Replacement/Programming .

#### Engine Coolant Level Indicator Control Circuit

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Important: : Ensure that Engine Coolant Level is not low, refer to Engine Cooling System before continuing diagnosis. Was the A Powertrain On Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to A Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Turn the ignition OFF.
2. Disconnect the PCM connector.
3. With a test light to battery positive voltage, probe the Engine Coolant Level indicator signal circuit at the PCM harness connector.

Is the test light ON?

--

Go to Step 6

Go to Step 3

3 |

1. Turn the ignition OFF.
2. Reconnect the PCM.
3. Turn the ignition ON.
4. Raise the vehicle.
5. Disconnect the Engine Coolant Level Indicator connector.
6. Connect a DMM to measure voltage between the Engine Coolant Level Indicator harness connector.

Does the DMM display voltage near the specified value?

B+

Go to Step 7

Go to Step 4

4 | Connect the DMM between the Engine Coolant Level Indicator signal circuit and chassis ground. Does the DMM display a voltage near the specified value? | B+ | Go to Step 8 | Go to Step 5
5 |

1. Check the Engine Coolant Level Indicator signal circuit for an open.
2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 12

Go to Step 10

6 |

1. Check the Engine Coolant Level Indicator circuit for a short to ground.
2. Repair as necessary, if no problem is found replace Engine Coolant Level Indicator switch.

Was a problem found?

--

Go to Step 12

Go to Step 10

7 |

1. Check for poor terminal connections at the Engine Coolant Level Indicator.
2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 12

Go to Step 9

8 | Locate and repair open in the Engine Coolant Level Indicator ground circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 12 | --
9 | Replace the Engine Coolant Level Indicator switch. Is the action complete? | -- | Go to Step 12 | --
10 | Refer to Instrument Panel Cluster (IPC) Microprocessor for diagnosis. Was a problem found? | -- | Go to Step 12 | Go to Step 11
11 | Important: : Important: Replacement PCM must be programmed. Refer to PCM Replacement/Programming . Replace the PCM. Is the action complete? | -- | Go to Step 12 | --
12 | Check for proper operation of Indicator light(s). Refer to Instrument Cluster System Check in Insrument Panel, Gauges and Console. Is the correct operation indicated? | -- | System OK | Go to Step 2