Refer to
Cooling Fans
.
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. Unlike the Quad Driver Modules (QDMs) used in prior model years, ODMs have the capability of diagnosing each output circuit individually. DTC P1651 set indicates an improper voltage level has been detected on ODM B output 1, which controls the Fan 1 relay.
Conditions for Setting the DTC
| • | The ignition is ON. |
| • | An improper voltage level has been detected on ODM B output 1 (the Fan 1 relay driver circuit). |
| • | The above conditions present for at least 30 seconds. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been 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 the scan tool Clear Information function or by disconnecting the PCM battery feed. |
Diagnostic Aids
Check for the following conditions:
| • | Poor connection at PCM - Inspect harness connectors for the following items: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | Poor terminal to wire connections |
| • | Damaged harness - Inspect the wiring harness for damage. |
| • | If the harness appears to be OK, disconnect the PCM, turn the ignition ON and observe a voltmeter connected between the Fan 1 relay driver circuit and ground at the PCM harness connector while moving connectors and wiring harnesses related to the Fan 1 relay. A change in voltage will indicate the location of the fault. |
Review the Fail Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
-
Normally, battery feed voltage should be present on the control circuit with the PCM disconnected and the ignition turned ON.
-
Checks for a shorted component or a short to B+ on the control circuit. Either condition would result in a measured current of over 500 milliamps. Also checks for a component that is going open while being operated, resulting in a measured current of 0 milliamps.
-
Checks for a short to B+ on the cooling fan relay #1 control circuit.
-
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.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
Is voltage near the specified value? | B+ | |||||||||
Does the current reading remain between the specified values? | 0.05-0.5 amps (50-500 mA) | |||||||||
Is voltage at the specified value? | 0V | |||||||||
5 | Locate and repair short to voltage in the cooling fan relay #1 control circuit. Refer to Repair Procedures in Electrical Diagnosis. Is action complete? | -- | -- | |||||||
6 |
Is the fuse open? | -- | ||||||||
7 |
Is action complete? | -- | -- | |||||||
8 |
Is voltage near the specified value? | B+ | ||||||||
9 |
Was a problem found? | -- | ||||||||
10 |
Was a problem found? | -- | ||||||||
11 |
Does the test light flash ON and OFF? | -- | Refer to Diagnostic Aids | |||||||
12 |
Was a problem found? | -- | ||||||||
13 | Locate and repair open in the battery feed circuit to the low speed cooling fan relay coil. Refer to Repair Procedures in Electrical Diagnosis. Is action complete? | -- | -- | |||||||
14 | Replace cooling fan relay #1. Is action complete? | -- | -- | |||||||
Replace the PCM. Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Is action complete? | -- | -- | ||||||||
16 |
Note test result; does the scan tool indicate DTC P1651 failed this ign? | -- | System OK |
