Refer to
Cell 20: Cooling Fan Controls
.
Circuit Description
Output Driver Modules (ODMs) are used by the PCM to turn on many of the current-driven devices that are needed to control various engine and Transaxle functions. Each ODM is capable of controlling up to 7 separate outputs by applying ground to the device which the PCM is commanding on. DTC P0481set indicates an improper voltage level has been detected, which controls the Cool Fan and Cool Fan 2 Relays.
Conditions for Running the DTC
The ignition is on.
Conditions for Setting the DTC
| • | An improper voltage level has been detected on the output circuit which controls the high speed fans. |
| • | The above conditions are present for at least 30 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. |
| • | The PCM writes the conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
Check for the following conditions:
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Poor terminal connection. |
| Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Intermittents and Poor Connections Diagnosis , and Connector Repairs Wiring Systems. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the harness appears to be OK, observe the sensor display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the sensor display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems. |
| • | Inspect the PCM and the engine grounds for clean and secure connections. |
If the DTC is determined to be intermittent, reviewing the Fail Records can be useful in determining when the DTC was last set.
Test Description
The number(s) below refer to the step number(s) on the diagnostic table:
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The Powertrain OBD System Check prompts you to complete some basic checks and store the freeze frame and failure records data on the scan tool.
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Listen for an audible click when the relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
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Tests for voltage at the coil feed side of the relays.
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Verifies that the PCM is providing ground to the relays.
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Tests if ground is constantly being applied to the relays.
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The PCM utilizes Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | ||
|
Important: : If you cannot determine if the relays are responding to the command, observe the fans. When High Speed Fans are commanded ON, Both fans should operate in low speed and after several seconds both fans should switch to high speed. If the fans are not operating properly continue with step 3 of this diagnosis.
Do both relays turn ON after several seconds and OFF with each command? | -- | Go to Diagnostic Aids | Go to Step 3 | |
Does the test lamp illuminate for both circuits? | -- | Go to Step 4 | Go to Step 10 | |
Does the test lamp turn ON after several seconds and OFF with each command for both relays? | -- | Go to Step 8 | Go to Step 5 | |
Does the test lamp remain illuminated with each command when probing either feed circuit? | -- | Go to Step 7 | Go to Step 6 | |
6 | Test the control circuits of each relay for a short to voltage or an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
7 | Test the control circuits of each relay for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
8 | Inspect for poor connections at the relays. Refer to Intermittents and Poor Connections Diagnosis , and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 |
9 | Inspect for poor connections at the PCM. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 |
10 | Repair the feed circuit of the effected relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the replacement? | -- | Go to Step 13 | -- |
11 | Replace the effected relay. Did you complete the replacement? | -- | Go to Step 13 | -- |
|
Important: : The replacement PCM must be programmed. place the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | Go to Step 13 | -- | |
13 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
