Local-CAN Inspection
| Inspection Item | Inspection Condition | (+) Probe | (-) Probe | Specification | ||
|---|---|---|---|---|---|---|
| Connector | Terminal | Connector | Terminal | |||
| Resistance inspection (IAU, WPC) |
|
IAU (component side) | 3 (Local-CAN high) | IAU (component side) | 11 (Local-CAN low) | Approx. 120Ω |
| WPC (component side) | 9 (Local-CAN high) | WPC (component side) | 8 (Local-CAN low) | Approx. 120Ω | ||
| Open in circuit inspection (IAU ↔ Door NFC module LH) |
|
IAU connector | 3 (Local-CAN high) | Door NFC module LH connector | 5 (Local-CAN high) | Approx. below 1Ω |
| IAU connector | 11 (Local-CAN low) | Door NFC module LH connector | 2 (Local-CAN low) | Approx. below 1Ω | ||
| Local-CAN oscilloscope (Door NFC module LH) |
|
Door NFC module LH connector | 5 (Local-CAN high) | Chassis ground | - | Fig.1 to 6 |
| Door NFC module LH connector | 2 (Local-CAN low) | Chassis ground | - | |||
Information
It is important to check CAN high and low at the same time to check the waveform of the CAN communication line. The CAN signal is in a bus idle state based on 2.5V (digital "1"), the high signal rises to 3.5V, the low signal falls to 1.5V, and the voltage difference between the high and low signals is "0" when 2V occurs. Is detected. In addition, it monitors whether the high and low signals have opposite voltages based on 2.5V like the waveform on the left, and monitors whether the current CAN signal is transmitted normally.
In CAN communication, a continuous "0" signal of 6 bits or more means occurrence of an error. 1 bit can be easily determined by obtaining the time when "SOF" (Start Of Frame), indicating the start of the frame, occurs. Check if the "0" signal of 6 bits or more occurs continuously during CAN communication waveform check.
- Reference voltage about 2.5V (high: 2.5V → 3.5V rise, low: 2.5V → 1.5V drop)
- Idle (2.5V) section of a certain period
- Constant data frame time
- High and low symmetrical frame shape
Good
- Fault might be intermittent and caused either by poor contact in connectors or wiring harness, or it has been repaired and control module memory is not cleared yet. Thoroughly check terminal of 12V battery, all connectors (and connections) for looseness, bending, corrosion, contamination, deterioration, and/or damage.
- Repair or replace as necessary and then Go to "VERIFICATION OF REPAIR " procedure.
No Good
- Check for a short circuit between the wiring and the chassis ground.
- If no problems were found with the circuits or connectors, replace door NFC module LH and then Go to "VERIFICATION OF REPAIR " procedure.