DTC C1438/59: Lost Communication with HV ECU: Procedure

1. Using the Techstream, check for any momentary interruption in the wire harness and connector corresponding to the DTC, refer to CHECK FOR INTERMITTENT PROBLEMS .
   ABS/VSC/TRAC
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   HV Communication Open	Hybrid vehicle communication open detection / Error or Normal	Error: Momentary interruption Normal: Normal	-

   OK

   There are no momentary interruptions.

   HINT: 

   Perform the above inspection before removing the sensor and connector.

NG → See step   3 

OK: Go to next step 

1. Turn the ignition switch off.
2. Clear the DTCs, refer to DTC CHECK / CLEAR .
3. Turn the ignition switch to ON (READY).
4. Drive the vehicle at a speed of 15 km/h (9 mph) or more for 10 seconds or more.
5. Check that no CAN communication system DTC is output (w/ Smart Key System:, refer to DIAGNOSIS SYSTEM , w/o Smart Key System:, refer to DIAGNOSIS SYSTEM ).
6. Check if the same DTC is recorded, refer to DTC CHECK / CLEAR .

   Result

   Result	Proceed to
   DTC (C1438/59) is not output	A
   DTC (C1438/59) is output	B
   DTC (CAN communication system DTC) is output (w/ Smart Key System)	C
   DTC (CAN communication system DTC) is output (w/o Smart Key System)	D

B → See step   6 

C → See step   7 

D → See step   8 

A → See step   5 

1. Turn the ignition switch off.
2. Repair or replace the harness or connector.
3. Check for any momentary interruption between the skid control ECU and the hybrid vehicle control ECU, refer to CHECK FOR INTERMITTENT PROBLEMS .
4. Confirm that there is no momentary interruption.

NEXT: Go to next step 

1. Turn the ignition switch off.
2. Clear the DTCs, refer to DTC CHECK / CLEAR .
3. Turn the ignition switch to ON (READY).
4. Drive the vehicle at a speed of 15 km/h (9 mph) or more for 10 seconds or more.
5. Check that no CAN communication system DTC is output (w/ Smart Key System:, refer to DIAGNOSIS SYSTEM , w/o Smart Key System:, refer to DIAGNOSIS SYSTEM ).
6. Check if the same DTC is recorded, refer to DTC CHECK / CLEAR .

   Result

   Result	Proceed to
   DTC (C1438/59) is not output	A
   DTC (C1438/59) is output	B
   DTC (CAN communication system DTC) is output (w/ Smart Key System)	C
   DTC (CAN communication system DTC) is output (w/o Smart Key System)	D

B → See step   6 

C → See step   7 

D → See step   8 

A → END