DTC P0688-1F: ECM/PCM Power Relay Sense Circuit Intermittent [12/2022 - ]: Procedure

1. Confirm whether the auxiliary battery terminals have been disconnected recently.

   Result

   Result	Proceed to
   Terminals have been disconnected.	A
   Terminals have not been disconnected.	B

Result: 

B 

See step  6

Result: 

A 

See step  2

Pre-procedure1

• Turn the ignition switch to ON (READY) from off.

• Confirm that the master warning illuminates.

  Result

  Result	Proceed to
  Master warning illuminates.	A
  Master warning does not illuminate.	B

  NOTE:

  DTC P0688-1F may be stored after disconnecting and reconnecting the auxiliary battery terminals. If this happens, the DTC will not be output if the ignition switch is turned off and then ON (READY) again. In this case, clear the DTCs to complete the inspection.

Post-procedure1

• Turn the ignition switch off.

Result: 

B 

END 

Result: 

A 

See step  3

1. Read and record the DTCs and freeze frame data.

   Powertrain > Hybrid Control > Trouble Codes 

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  4

Pre-procedure1

• None.

• Clear the DTCs and freeze frame data.

  Powertrain > Hybrid Control > Clear DTCs 

  Result

  Proceed to
  NEXT

Post-procedure1

• Turn the ignition switch off and wait for 2 minutes or more.

Result: 

NEXT 

See step  5

Pre-procedure1

• None.

• Check for DTCs.

  Powertrain > Hybrid Control > Trouble Codes 

  Result

  Result	Proceed to
  Only P0688-1F is output	A
  P0688-1F and other DTCs are output	B

Post-procedure1

• Turn the ignition switch off.

Result: 

B 

GO TO DTC CHART (HYBRID CONTROL SYSTEM). Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2022 - ] 

Result: 

A 

See step  6

1. Check the connection of the auxiliary battery terminal.

   OK

   The terminal is connected securely and there is no contact problem.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

CONNECT SECURELY 

Result: 

OK 

See step  7

See step  1

Result

Result: 

NG 

CONNECT SECURELY 

Result: 

OK 

See step  8

Pre-procedure1

• Remove the IGCT-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
• Disconnect the hybrid vehicle control ECU connector.

• Measure the resistance according to the value(s) in the table below.

  Standard Resistance

  Tester Connection	Condition	Specified Condition	Result
  K11-8 (+B1) - 3 (IGCT-MAIN NO. 1 relay holder)	Ignition switch off	Below 1 Ω	Ω

  Result

  Proceed to
  OK
  NG

Post-procedure1

• Reconnect the hybrid vehicle control ECU connector.
• Reinstall the IGCT-MAIN NO. 1 relay.

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  9

1. Check for intermittent problems.

   HINT: 

   Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2022 - ]

   1. Check the connection and terminal contact pressure of the connectors and wire harnesses between the hybrid vehicle control ECU and the No. 1 engine room relay block and No. 1 junction block assembly.
   2. When the ignition switch is ON (READY), jiggle the connectors and wire harnesses between the hybrid vehicle control ECU and the No. 1 engine room relay block and No. 1 junction block assembly.

   Result

   Result	Proceed to
   Problem symptom does not recur.	A
   Problem symptom recurs.	B

Result: 

A 

REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [12/2022 - 03/2023]  , or refer to  REMOVAL [03/2023 - ] 

Result: 

B 

REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA