Test Procedures

JH1 CONTINUOUS MEMORY DTCS P0726 AND P0727: CLEAR AND RETRIEVE TCM CONTINUOUS DTCS

NOTE: Repair the PCM continuous memory DTC P0320 before proceeding any further.

NOTE: Clearing the TCM DTCs will erase any TCM recorded freeze frame data. Make sure to record any TCM freeze frame information before proceeding any further. Refer to the diagnostic tool instruction manual for freeze frame PID menu.

Clear and retrieve TCM continuous DTCs.

Are the TCM DTCs P0726 or P0727 present during self-test?

Yes	No
A hard fault is present. GO to JH2.	CHECK the CTO circuit for an intermittent fault. GO to JH8.

JH2 COMPARE TCM CALCULATED AND RECEIVED ENGINE RPM TO THE ACTUAL ENGINE RPM

NOTE: The RPM PID indicates the engine speed the TCM calculated using generator speed. The ENG CTO PID indicates the engine speed the TCM receives from the PCM through the CTO circuit.

NOTE: If the engine cranks but does not start, refer to SYMPTOM CHARTS - HYBRID ESCAPE , and Diagnose the No Start, Normal Crank symptom.

Start the engine using the engine running diagnostic mode. Refer to DIAGNOSTIC MODES .
Allow the engine to idle at the normal operating temperature.
Access the TCM and monitor the RPM and ENG CTO PIDs.

Are both RPM PID readings within 1,000 RPM range of engine idle RPM?

Yes	No
INSTALL a new transaxle assembly.	GO to JH3.

JH3 CHECK THE CTO FOR A SHORT TO POWER IN THE HARNESS

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

Measure the voltage between:

( + ) Transaxle Assembly-B Connector, Harness Side	( - ) Vehicle Battery
CTO - Pin 1	Negative terminal

Is the voltage less than 1 V?

Yes	No
Key in OFF position. GO to JH4.	Key in OFF position. REPAIR the short circuit to PWR.

JH4 CHECK THE CTO CIRCUIT FOR A SHORT TO GND IN THE HARNESS

Measure the resistance between:

( + ) Transaxle Assembly-B Connector, Harness Side	(-) Vehicle Battery
CTO - Pin 1	Negative terminal

Is the resistance greater than 10K ohms?

Yes	No
GO to JH5.	REPAIR the short circuit to GND.

JH5 CHECK THE CTO CIRCUIT FOR AN OPEN IN THE HARNESS

Measure the resistance between:

( + ) Transaxle Assembly-B Connector, Harness Side	(-) PCM Connector, Harness Side
CTO - Pin 1	CTO - Pin T46

Is the resistance less than 5 ohms?

Yes	No
GO to JH6.	REPAIR the open circuit.

JH6 CHECK FOR THE CTO CIRCUIT SHORTED TO SIGNALS IN THE SAME HARNESS

Measure the resistance between:

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

Are the resistances greater than 10K ohms?

Yes	No
GO to JH7.	REPAIR the short circuit. ISOLATE the fault and REPAIR as necessary.

JH7 CHECK THE CTO SIGNAL FROM THE PCM

CAUTION: While conducting checks with a running engine make sure adequate safety precautions are observed to prevent contact with moving engine parts. For example make sure ties or loose clothing do not come into contact with the cooling fan or drive belts.

PCM connector connected.
Transaxle Assembly-B connector connected.
Isolate the CTO pin from the transaxle-B connector.
Start the engine using the engine running diagnostic mode. Refer to DIAGNOSTIC MODES .

Measure the frequency between:

( + ) Transaxle Assembly-B Connector, Harness Side	( - ) Vehicle Battery
CTO - Pin 1	Negative terminal

Is the frequency between 15 Hz -155 Hz?

Yes	No
Key in OFF position. INSTALL a new transaxle assembly.	INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .

JH8 CHECK THE CTO CIRCUIT FOR INTERMITTENT FAULTS

CAUTION: While conducting checks with a running engine ensure adequate safety precautions are observed to prevent contact with moving engine parts. For example ensure ties or loose clothing do not come into contact with the cooling fan or drive belts.

Start the engine using the engine running diagnostic mode. Refer to DIAGNOSTIC MODES .
Access the TCM and monitor the ENG CTO PID.
Carefully wiggle all accessible wiring and connectors associated with the circuit and look for a change in the PID state.

Is a fault indicated during the wiggle test?

Yes	No
Key in OFF position. REPAIR as necessary.	Key in OFF position. GO to Pinpoint Test Z .