For 1990-2009 cars

## Powertrain Control Module Controlled Warning Lamps Diagnosis Low Oil Level Circuit

Refer to

#### Engine Oil Pressure Sensor, Transaxle Range Switch, IAC Valve

Engine Controls Components
Information Sensors 1
Vehicle Speed Sensor
Heated Oxygen Sensors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The Engine Oil Level Indicator is a simple float switch that grounds the Engine Oil Level Indicator circuit when oil level is OK. The PCM checks the Engine Oil Level switch circuit at start-up. Before checking the state of the Engine Oil Level switch, the PCM performs a test routine based on time and engine coolant temperature to ensure that the engine oil has drained back into the sump. To test for low oil level at start-up, one of the following conditions must be present:

• | If the engine coolant temperature was between 15° (59° ) and 90° C (194° F) at the last key OFF, the engine coolant temperature at key ON must be at least 12° C (22° F) cooler than the engine coolant temperature at the last key OFF.

• | If the engine coolant temperature was higher than 90° C (194° F) at the last key OFF, the time between last key OFF and the present key ON must be sufficient to allow the oil to drain back to the sump. The PCM will remain powered up for 10 seconds to ensure that the oil has drained back to the sump. If the key is turned back ON while the PCM is still powered up, the oil level will not be tested.

The Low Oil Level Lamp will be illuminated for about a minute when the PCM checks for low oil level and the Engine Oil Level switch indicates that a low oil level condition exists (Engine Oil Level switch circuit not grounded). When the ignition is first turned On, the PCM commands the Low Oil Level lamp On for a brief period of time to test the bulb.

### Diagnostic Aids

For diagnosis of the instrument panel, perform the System Check in the Instrument Panel Cluster section of Electrical Diagnosis.

Check for the following conditions:

• | Poor connection at PCM or oil level sensor. 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

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

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 and Programming Procedures in Powertrain Control Module (PCM) and Sensors.

#### Low Engine Oil Level Indicator Control Circuit

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Important: Ensure that engine oil level is not low (as indicated on dipstick) before continuing diagnosis. Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain OBD System Check
2 |

1. Ignition OFF, disconnect the PCM connector.
2. With a test light to B+, probe the Oil Level Switch signal circuit at the PCM.

Is the test light ON?

--

Go to Step 6

Go to Step 3

3 |

1. Ignition OFF, reconnect the PCM.
2. Ignition ON.
3. Raise the vehicle.
4. Disconnect the Oil Level Switch connector.
5. Connect a DVM to measure voltage between the Oil Level Switch terminals.

Does the DVM display voltage near the specified value?

B+

Go to Step 7

Go to Step 4

4 | Connect the DVM between the Oil Level Switch signal circuit and chassis ground. Does the DVM display a voltage near the specified value? | B+ | Go to Step 8 | Go to Step 5
5 |

1. Check the Oil Level Switch signal circuit for an open.
2. If a problem is found, repair as necessary. Refer to Repair Procedures in Electrical Diagnosis.

Was a problem found?

--

Go to Step 12

Go to Diagnostic Aids

6 |

1. Check for poor terminal connections at the PCM.
2. If a problem is found, repair as necessary. Refer to Repair Procedures in Electrical Diagnosis.

Was a problem found?

--

Go to Step 12

Go to Step 10

7 |

1. Check for poor terminal connections at the Oil Level Switch.
2. If a problem is found, repair as necessary. Refer to Repair Procedures in Electrical Diagnosis.

Was a problem found?

--

Go to Step 12

Go to Step 9

8 | Locate and repair open in the Oil Level Switch ground circuit. Refer to Repair Procedures in Electrical Diagnosis. Is action complete? | -- | Go to Step 12 | --
9 | Replace the Oil Level Switch. Is action complete? | -- | Go to Step 12 | --
10 | Refer to Engine Electrical for Instrument Panel Cluster (IPC) Microprocessor for diagnosis Was A problem found? | -- | Go to Step 12 | Go to Step 11
11 | Replace the PCM. Important: Replacement PCM must be programmed. Refer to PCM Replacement/Procedure? Is action complete? | -- | Go to Step 12 | --
12 | Check for proper operation of Indicator light(s). Refer to IPC Diagnosis in section. Is correct operation indicated? | -- | Repair Complete | Go to Step 2

## Powertrain Control Module Controlled Warning Lamps Diagnosis Low Coolant Level circuit

Refer to

#### Engine Oil Pressure Sensor, Transaxle Range Switch, IAC Valve

Engine Controls Components
Information Sensors 1
Vehicle Speed Sensor
Heated Oxygen Sensors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Diagnostic Aids

For diagnosis of the instrument panel, perform the System Check in the Instrument Panel Cluster section of Electrical Diagnosis.

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

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

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 and Programming Procedures in Powertrain Control Module (PCM) and Sensors.

#### Low 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 Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain OBD System Check
2 |

1. Ignition OFF, disconnect the PCM connector.
2. With a test light to B+, probe the Engine Coolant Level indicator signal circuit at the PCM.

Is the test light on?

--

Go to Step 6

Go to Step 3

3 |

1. Ignition OFF, reconnect the PCM.
2. Ignition ON.
3. Raise the vehicle.
4. Disconnect the Engine Coolant Level Indicator connector.
5. Connect a DVM to measure voltage between the Engine Coolant Level Indicator harness connector.

Does the DVM display voltage near the specified value?

B+

Go to Step 7

Go to Step 4

4 | Connect the DVM between the Engine Coolant Level Indicator signal circuit and chassis ground. Does the DVM 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 Repair Procedures in Electrical Diagnosis).

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.

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 Repair Procedures in Electrical Diagnosis).

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 Repair Procedures in Electrical Diagnosis). Is action complete? | -- | Go to Step 12 | --
9 | Replace the Engine Coolant Level Indicator. Is action complete? | -- | Go to Step 12 | --
10 | Refer to Section 8C1 for Intrument Panel Cluster (IPC) Microprocessor for diagnosis Was a problem found? | -- | Go to Step 12 | Go to Step 11
11 | Replace the PCM. Important: Replacement PCM must be programmed. Refer to On-Vehicle Service in Powertrain Control Module and Sensors for procedures. Is action complete? | -- | Go to Step 12 | --
12 | Check for proper operation of Indicator light(s). Refer to IPC Diagnosis in section 8C1 Is correct operation indicated? | -- | Repair Complete | Go to Step 2

## Powertrain Control Module Controlled Warning Lamps Diagnosis Generator Lamp Circuit

Engine Controls Components
Engine Oil Pressure Sensor, Transaxle Range Switch, IAC Valve
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Diagnostic Aids

For diagnosis of the instrument panel, perform the System Check in the Instrument Panel Cluster section of Electrical Diagnosis.

Check for the following conditions:

• | Poor connection at PCM or Generator. 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

1. 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 and Programming Procedures in Powertrain Control Module (PCM) and Sensors.

#### Generator Lamp Control Circuit

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain OBD System Check
2 | If any DTCs are set repair DTCs first. Are any DTCs Set? | -- | Go to applicable DTC table | Go to Step 3
3 | Check the Generator input and output circuits between the Generator and the PCM for continuity. Do any of the circuits need repair? | -- | Go to Step 4 | Go to Step 5
4 | Repair as necessary, refer to Electrical Diagnosis for repair procedures. Is action complete? | -- | Go to Step 8 | --
5 | Refer to Instrument Panel and Console in section 8C to diagnose Instrument Panel Cluster warning lamps. Was a problem found? | -- | Go to Step 8 | Go to Step 6
6 | Refer to Electrical Diagnosis in section 6D3 to diagnose the charging system Was a problem found? | -- | Go to Step 8 | Go to Step 7
7 | Replace the PCM. Important: The Replacement PCM Must be programmed. Refer to On-Vehicle Service in Powertrain Control Module and Sensors for procedures. Is action complete? | -- | Go to Step 8 | --
8 | Check for proper operation of Indicator light(s). Refer to IPC diagnosis in section 8C1 Is correct operation indicated? | -- | Repair complete | Go to Step 3

## Powertrain Control Module Controlled Warning Lamps Diagnosis Tach Output Circuit

Refer to

#### DLC, Instrument Panel, Engine Compartment Fuse Center

Engine Controls Components
Powertrain Control Module Controlled Warning Lamps
Knock Sensor, Camshaft Position Sensor, Crankshaft Position Sensor, Ignition Control Module
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

### Diagnostic Aids

For diagnosis of the instrument panel, perform the System Check in the Instrument Panel Cluster (IPC) Microprocessor.

Check for the following conditions:

• | Poor connection at PCM. 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.

### Test Description

An example test description follows:

1. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed. Refer to PCM replacement and programming procedures in Powertrain Control Module and Sensors.

#### Tachometer Control Circuit

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to OBD System Check
2 | Are any DTCs set? | -- | Go to applicable DTC table | Go to Step 3
3 | Install scan tool, monitor engine RPM. Does scan tool engine RPM indicate approximate engine operation? | -- | Go to Step 4 | Go to Step 5
4 | Monitor the Tachometer output on the Instrument Panel Cluster with engine RPM on scan tool. Do they closely match each other? | -- | Go to Step 9 | Go to Step 5
5 | Refer to Electrical Diagnosis for diagnosing Serial Data circuit. Was a problem found? | -- | Go to Step 9 | Go to Step 6
6 | Refer to Instrument Panel Cluster in section 8C1 to diagnose the Tachometer. Was a problem found? | -- | Go to Step 9 | Go to Step 7
7 | Install scan tool to known good vehicle and monitor engine RPM. Does engine RPM on scan tool indicate approximate engine operation? | -- | Go to Step 8 | Check scan tool for proper operation
8 | Replace the PCM. Important: Replacement PCM must be programmed. Refer to On-Vehicle Service in Powertrain Control Module and Sensors for Procedures. Is action Complete? | -- | Go to Step 9 | --
9 | Check for proper operation of the Tachometer. Refer to IPC Diagnosis in section 8C1. Is correct operation indicated? | -- | Repair complete | Go to Step 2