Many malfunctions in the electrical system are caused by poor connection. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure.
	▶ Go to "CAN Communication Line Inspection" procedure.

Connect all control module connector.

Ignition "ON".

Make CAN communication wake up status.

Back probe and measure signal waveform of Pin No. 11(Low) terminal of Data Link Connector(DLC) and chassis ground with VMI.

Back probe and measure signal waveform of Pin No. 3(High) terminal of Data Link Connector(DLC) and chassis ground with VMI.

Fig.1) Normal C-CAN signal waveform

Are the measured signal waveforms OK?

	▶ Fault is intermittent caused by poor contact in the sensor’s and/or EPS ECU connector or was repaired and EPS ECU memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
	▶ Go to "CAN communication circuit inspection (EPS ↔ ECM/TCM)" procedure.

Ignition "OFF"

Disconnect EPS ECU connector and ECM or TCM harness connector.

Measure resistance between Pin No. 7(C-CAN-HIGH) of the EPS ECU harness connector and Pin No. 57(C-CAN-HIGH) of the ECM harness connector.(1.6MPI Only)

Measure resistance between Pin No. 7(C-CAN-HIGH) of the EPS ECU harness connector and Pin No. 85(C-CAN-HIGH) of the ECM harness connector.(1.0T-GDI, 1.6GDI, 1.6T-GDI Only)

Measure resistance between Pin No. 7(C-CAN-HIGH) of the EPS ECU harness connector and Pin No. 44(C-CAN-HIGH) of the TCU harness connector.(1.4U-II, 1.6U-II Only)

Measure resistance between Pin No. 7(C-CAN-HIGH) of the EPS ECU harness connector and Pin No. 41(C-CAN-HIGH) of the ECM harness connector.(1.4MPI Only)

Measure resistance between Pin No. 8(C-CAN-LOW) of the EPS ECU harness connector and Pin No. 79(C-CAN-LOW) of the ECM harness connector.(1.6MPI Only)

Measure resistance between Pin No. 8(C-CAN-LOW) of the EPS ECU harness connector and Pin No. 63(C-CAN-LOW) of the ECM harness connector.(1.0T-GDI, 1.6GDI, 1.6T-GDI Only)

Measure resistance between Pin No. 8(C-CAN-LOW) of the EPS ECU harness connector and Pin No. 45(C-CAN-LOW) of the TCU harness connector.(1.4U-II, 1.6U-II Only)

Measure resistance between Pin No. 8(C-CAN-LOW) of the EPS ECU harness connector and Pin No. 29(C-CAN-LOW) of the ECM harness connector.(1.4MPI Only)

Fig.1) GDS Multimeter resistance check

Is the measured resistance within specification?

	▶ Go to "Check short to ground in CAN communication line" procedure.
	▶ If the measured value is ∞Ω, repair or replace the open in CAN High/CAN Low circuit. And then, go to "Verification of Vehicle Repair" procedure.

Ignition "OFF"

Disconnect Battery (-) terminal.

Refer to "Shop Manual" and disconnect other control unit connector that connected to C-CAN Communication circuit.

Measure resistance between Pin No. 3(C-CAN High) terminal and Pin No. 11(C-CAN Low) terminal of Data Link Connector(DLC).

Fig.1) GDS Multimeter resistance check

Is the measured resistance within specifications?

	▶ Go to "Component Inspection" procedure.
	▶ Repair short in C-CAN Communication circuit or replace as necessary and then go to "Verification of Vehicle Repair" procedure.