Circuit Inspection
Module Inspection
| Module Inspection | ||||||
|---|---|---|---|---|---|---|
| Inspection Item | Inspection Condition | (+) Probe | (-) Probe | Specification | ||
| Connector | Terminal | Connector | Terminal | |||
| Power inspection (MCU ↔ Chassis ground) |
|
MCU connector | 33, 38 (B+ Input) | Chassis ground | - | B+ |
| MCU connector | 24 (ON/START Input) | Chassis ground | - | B+ | ||
|
MCU connector | 34 (IG3 Input) | Chassis ground | - | B+ | |
| Open in Circuit Inspection (MCU ↔ Chassis ground) |
|
MCU connector | 35, 40 (ground) | Chassis ground | - | Approx. below 1Ω |
Good
- Go to "CAN Communication circuit Inspection (G-CAN)" procedure.
No Good
- Repair as necessary and then go to "Verification of Repair " procedure.
| CAN communication circuit Inspection (G-CAN) | ||||||
|---|---|---|---|---|---|---|
| Inspection Item | Inspection Condition | (+) Probe | (-) Probe | Specification | ||
| Connector | Terminal | Connector | Terminal | |||
| G-CAN oscilloscope (MCU ↔ Chassis ground) |
|
MCU connector | 1 (G-CAN high) | Chassis ground | - | Fig.1 to 6 |
| MCU connector | 2 (G-CAN low) | Chassis ground | - | |||
| Open in Circuit Inspection (MCU ↔ IEBU) |
|
MCU connector | 1 (G-CAN high) | IEBU connector | 21 (G-CAN high) | Approx. below 1Ω |
| MCU connector | 2 (G-CAN low) | IEBU connector | 22 (G-CAN low) | Approx. below 1Ω | ||
| Resistance inspection (ICU, BMU) |
|
ICU (component side) | 29 (G-CAN high) | ICU (component side) | 30 (G-CAN low) | Approx. 120Ω |
| BMU (component side) | 20 (G-CAN high) | BMU (component side) | 19 (G-CAN low) | Approx. 120Ω | ||
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 battery, all connectors (and connections) for looseness, bending, corrosion, contamination, deterioration, and/or damage.
- Repair or replace as necessary and go to "Verification of Repair " procedure.
No Good
- Carefully re-do this troubleshooting guide steps.
- If no problems were found with the circuits or connectors, replace the MCU and go to "Verification of Repair " procedure.