Circuit Inspection
| Module Circuit Inspection | ||||||
|---|---|---|---|---|---|---|
| Inspection Item | Inspection Condition | (+) Probe | (-) Probe | Specification | ||
| Connector | Terminal | Connector | Terminal | |||
| Power inspection (SCU ↔ Chassis ground) |
|
SCU connector | 10 (B+ Input) | Chassis ground | - | B+ |
|
SCU connector | 16 (IG3 Input) | Chassis ground | - | B+ | |
| Open in circuit inspection (SCU ↔ Chassis ground) |
|
SCU connector | 9, 19, 20 (ground) | Chassis ground | - | Approx. below 1Ω |
Good
- Go to "CAN Communication circuit Inspection (P-CAN)" procedure.
No Good
- Repair open or short in circuit and then go to "Verification of Repair " procedure.
| CAN communication circuit Inspection (P-CAN) | ||||||
|---|---|---|---|---|---|---|
| Inspection Item | Inspection Condition | (+) Probe | (-) Probe | Specification | ||
| Connector | Terminal | Connector | Terminal | |||
| P-CAN oscilloscope (SCU - Chassis ground) |
|
SCU connector | 6 (P-CAN high) | Chassis ground | - | Fig.1 to 6 |
| SCU connector | 7 (P-CAN low) | Chassis ground | - | |||
| Open in circuit inspection (SCU -ICU) |
|
SCU connector | 6 (P-CAN high) | ICU connector | 19 (P-CAN high) | Approx. below 1Ω |
| SCU connector | 7 (P-CAN low) | ICU connector | 20 (P-CAN low) | Approx. below 1Ω | ||
| Resistance inspection (A/C module, ICU) |
|
ICU (component side) | 19 (P-CAN high) | ICU (component side) | 20 (P-CAN low) | Approx. 120Ω |
| A/C module (component side) | 77 (P-CAN high) | A/C module (component side) | 78 (P-CAN low) | Approx. 120Ω | ||
Information
It is important to check CAN high and low at the same time to check the wave form 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
- Go to "CAN Communication circuit Inspection (C-CAN)" procedure.
No Good
- Repair open or short in circuit and then go to "Verification of Repair " procedure.
| CAN communication circuit Inspection (C-CAN) | ||||||
|---|---|---|---|---|---|---|
| Inspection Item | Inspection Condition | (+) Probe | (-) Probe | Specification | ||
| Connector | Terminal | Connector | Terminal | |||
| C-CAN oscilloscope (ICU ↔ Chassis ground) |
|
ICU connector | 21 (C-CAN high) | Chassis ground | - | Fig.1 to 6 |
| ICU connector | 22 (C-CAN low) | Chassis ground | - | |||
| Open in circuit inspection (IEBU ↔ ICU) |
|
IEBU connector | 25 (C-CAN high) | ICU connector | 21 (C-CAN high) | Approx. below 1Ω |
| IEBU connector | 26 (C-CAN low) | ICU connector | 22 (C-CAN low) | Approx. below 1Ω | ||
| Resistance inspection (ICU, SRSCM) |
|
ICU (component side) | 21 (C-CAN high) | ICU (component side) | 22 (C-CAN low) | Approx. 120Ω |
| SRSCM (component side) | 27 (C-CAN high) | SRSCM (component side) | 26 (C-CAN low) | Approx. 120Ω | ||
Information
It is important to check CAN high and low at the same time to check the wave form 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. Therefore check terminal of battery, all connectors and connections for looseness, bending, corrosion, contamination, deterioration, and/or damage.
- Repair open or short in circuit and then 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 SCU and go to "Verification of Repair " procedure.