Pinpoint Test I: U0301

Refer to MODULE COMMUNICATIONS NETWORK for schematic and connector information.

Normal Operation and Fault Conditions

On some vehicles, it is possible to install an SOBDMC that is compatible with the drivetrain, but not with the GSM. An SOBDMC that is compatible with the GSM will send out a compatibility communication signal to the GSM. Each time the GSM wakes up from sleep mode, it will check to make sure that the SOBDMC installed in the vehicle is compatible.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
GSM U0301:00	Software Incompatibility with ECM/PCM: No Sub Type Information	For this vehicle, this DTC indicates the GSM did not receive a compatibility signal from the SOBDMC. When this DTC is set, the GSM will not allow the vehicle to shift out of park.

Possible Sources

Low system voltage
Incorrect PMI
Incorrect or corrupted SOBDMC calibration
Connectors damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals
SOBDMC fault

I1 CHECK ALL MODULES FOR LOW VOLTAGE DIAGNOSTIC TROUBLE CODES (DTCS)
- Using a diagnostic scan tool, review all continuous memory diagnostic trouble codes (CMDTCs) in all modules.
Is a low voltage DTC set in any module?

Yes RESOLVE the vehicle voltage concern first. REFER to: Charging System .

No GO to I2

I2 CHECK FOR OTHER CAUSES OF COMMUNICATION CONCERNS

NOTE: If new modules were installed prior to the DTC being set, the module configuration can be incorrectly set during the PMI or the PMI may not have been carried out.
- Check the vehicle service history for recent service actions related to the SOBDMC. If recent service history is found:
  - verify correct replacement module was installed
    - HVBOM may be used to verify correct part application
  - verify the configuration of replacement module was correct
    - re-configure module using as-built data if prior configuration is suspect
  - verify the module was not obtained from a like vehicle and installed into customer vehicle
    - return the swapped module to source vehicle and obtain new replacement module
Were any causes of a communication concern found in the vehicle service history?

Yes PROGRAM or INSTALL a new module as necessary.

No GO to I3

I3 PROGRAM THE SOBDMC (SECONDARY ON-BOARD DIAGNOSTIC CONTROL MODULE C) WITH THE LATEST CALIBRATION

NOTE: If a GSM self-test is carried out, the driver door must be fully closed. A false P166B DTC may set if the driver door is not fully closed during the self-test.
- Using a diagnostic scan tool, program the SOBDMC with the latest calibration. REFER to: Module Programming .
- Using a diagnostic scan tool, clear all diagnostic trouble codes (DTCs) from the GSM.
- Ignition OFF.
- Wait 10 seconds.
- Start the engine.
- Move the selector lever to each gear position. Let the vehicle move both forward and in reverse.
- Using a diagnostic scan tool, carry out the GSM self-test.
Is DTC U0301 present in the GSM?

Yes GO to I4

No The concern is not present at this time. It may have been caused by an incorrect or corrupted PCM calibration.

I4 CHECK FOR CORRECT SOBDMC (SECONDARY ON-BOARD DIAGNOSTIC CONTROL MODULE C) OPERATION

Ignition OFF.

Disconnect and inspect all SOBDMC connectors.

Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

Connect all SOBDMC connectors. Make sure they seat and latch correctly.

Operate the system and verify the concern is still present.

Is the concern still present?

Yes	CHECK for an applicable TSB, GSB, SSM, or FSA. If a service bulletin exists for this concern, discontinue this test and follow bulletin instructions. If none address this concern, INSTALL a new SOBDMC. REFER to: Inverter System Controller [SOBDMC] .

No	The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.