Test Procedure

TC1: DIAGNOSTIC TROUBLE CODE (DTC) P0A23: VERIFY THAT THE CONCERN IS PRESENT
- Record and clear all continuous memory DTCs.
- Retrieve the PCM continuous memory DTCs.
- Is DTC P0A23 present?
- Yes: GO to TC2.
- No: GO to TC7.

TC2: CHECK THE TGAC CIRCUIT FOR AN OPEN IN THE HARNESS

Key in OFF position.
PCM connector disconnected.
Transaxle Assembly-B connector disconnected.

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) Transaxle Assembly-B Connector, Harness Side
TGAC - Pin T5	TGAC - Pin 9

Is the resistance less than 5 ohms?

Yes: GO to TC3.
No: REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

TC3: CHECK THE TGAC CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS

Key ON, engine OFF.

Measure the voltage between:

(+) PCM Connector, Harness Side	(-) Vehicle Battery
TGAC - Pin T5	Negative terminal

Is the voltage less than 1 V?

Yes: GO to TC4.
No: REPAIR the circuit.
CLEAR the DTCs. REPEAT the self-test.

TC4: CHECK THE TGAC CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

Key in OFF position.

Measure the resistance between:

(+) PCM Connector, Harness Side	(-) Vehicle Battery
TGAC - Pin T5	Negative terminal

Is the resistance greater than 10K ohms?

Yes: GO to TC5.
No: REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

TC5: CHECK FOR THE TGAC CIRCUIT SHORTED TO SIGNALS IN THE SAME HARNESS

Measure the resistance between:

(+) Transaxle Assembly-B Connector, Harness Side	(-) Transaxle Assembly-B Connector, Harness Side
TGAC - Pin 9	ISDN2 - Pin 7
TGAC - Pin 9	GSDN - Pin 10
TGAC - Pin 9	CTO - Pin 1
TGAC - Pin 9	TMAC - Pin 4
TGAC - Pin 9	MSDN - Pin 5

Are the resistances greater than 10K ohms?

Yes: GO to TC6.
No: REPAIR the circuit.
CLEAR the DTCs. REPEAT the self-test.

TC6: TGAC FUNCTIONAL TEST

PCM connector connected.
Transaxle Assembly-B connector connected.
Isolate the TGAC pin from the Transaxle-B connector.

Connect a 5 amp fused jumper wire between the following:

Point A Transaxle Assembly-B Connector, Harness Side	Point B Transaxle Assembly-B Connector, Harness Side
TGAC - Pin 9	TMAC - Pin 4

Key ON, engine running. Does the engine start now?

Yes: INSTALL a new transaxle assembly. REFER to the AUTOMATIC TRANSAXLE - HYBRID .
No: GO to TC8.

TC7: CHECK THE TGAC CIRCUIT FOR AN INTERMITTENT CONCERN
- Key ON, engine OFF.
- Access the PCM and monitor the TGAC PID.
- Carefully wiggle all accessible wiring and connectors associated with the circuit and look for a change in the PID state.
- Is a concern present during the wiggle test?
- Yes: REPAIR as necessary.
  CLEAR the DTCs. REPEAT the self-test.
- No: GO to PINPOINT TEST Z .
TC8: CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Visually inspect for:
  - pushed out pins
  - corrosion
- Connect all the PCM connectors and make sure they seat correctly.
- Carry out the PCM self-test and verify the concern is still present.
- Is the concern still present?
- Yes: INSTALL a new PCM.
  REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .
- No: The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.