AITO M5 Charging System Precision Test Guide

Fault Background

The precision test of the charging system on the AITO M5 is divided into five groups, A to E: OBC coolant over-temperature family (P13004B/P130023, two water pump power/ground link point-to-point checks), OBC AC input/output protection family (P1301xx/P1302xx/P1303xx/P130749, over a dozen codes, converging to "check power supply equipment → replace OBC"), DCAC inverter family (P1304xx/P1305xx/P13061A inverter insulation detection/residual voltage protection), high-voltage interlock family (fast-charge socket/battery pack rear harness/rear motor harness, checked section by section), and battery voltage family (B111716/17). The water pump point-to-point criteria are clear: GCU electronic water pump FCR14-3 battery voltage (LRP19), FCR14-2 to ground <1Ω (DT49); rear motor electronic water pump RCR10-3 battery voltage (LRP17), RCR10-2 to ground <1Ω (DT10). This article is organized as a service guide.

Test A: OBC Coolant Over-Temperature Family

P13004B OBC coolant over-temperature fault / P130023 OBC coolant high-temperature derating protection:

1. Check whether the coolant level is normal → Use the diagnostic scan tool to clear DTCs and retest (if not reproduced = intermittent fault);
2. Check for leaks/blockages item by item: low-temperature cooling circuit hoses, low-temperature radiator, low-temperature coolant reservoir, generator controller two-in-one assembly, on-board charger assembly, four-way valve;
3. GCU electronic water pump power circuit LRP19 (BR-BL): Power on → Disconnect electronic water pump connector FCR14 → Measure whether terminal 3 has battery voltage—if abnormal, repair LRP19 open or short circuit;
4. GCU electronic water pump ground circuit DT49 (BK): Power down → Disconnect FCR14 → Measure whether terminal 2 to ground is <1Ω—if normal, replace the GCU electronic water pump; if abnormal, repair DT49;
5. Rear motor electronic water pump power circuit LRP17 (GB): Power on → Disconnect connector RCR10 → Measure whether terminal 3 has battery voltage—if abnormal, repair LRP17;
6. Rear motor electronic water pump ground circuit DT10 (BK): Power down → Measure whether terminal 2 of RCR10 to ground is <1Ω—if normal, replace the rear motor electronic water pump; if abnormal, repair DT10;
7. If the issue still cannot be resolved → Replace the on-board charger (OBC) assembly.

Test B: OBC AC Input/Output Protection Family

P130116 AC input undervoltage / P130117 AC input overvoltage / P130125 AC input voltage frequency abnormal / P130119 AC input overcurrent / P130216 High-voltage DC output undervoltage / P130217 High-voltage DC output overvoltage / P130219 High-voltage DC output overcurrent / P130214 High-voltage DC output short circuit / P130316 High-voltage side hardware undervoltage / P130317 High-voltage side hardware overvoltage / P130749 OBC internal circuit fault:

Check whether the slow-charge/fast-charge charging socket assembly connector and the OBC connector are loose → Clear DTCs and retest → Check whether the power supply equipment is normal → Replace the on-board charger (OBC) assembly and retest system operation.

Test C: DCAC Inverter Family

P130416 High-voltage DC input undervoltage / P130417 Overvoltage / P130419 Overcurrent / P130516 AC output undervoltage / P130517 Overvoltage / P130519 Overcurrent / P130514 Short circuit / P13051F Overload / P13061A DCAC inverter insulation detection fault / P13061C DCAC inverter output residual voltage protection: Same approach as Group B—check socket connector and OBC connector → Clear DTCs and retest → Check power supply equipment → Replace the on-board charger (OBC) assembly.

Test D: High-Voltage Interlock Family

Check whether the connectors of the fast-charge charging socket assembly, battery pack rear high-voltage harness assembly, and rear motor high-voltage harness assembly are loose → Clear DTCs and retest → Disconnect section by section, check the high-voltage interlock signal for short to ground / short to power / open circuit—if abnormal, replace the fast-charge charging socket assembly / battery pack rear high-voltage harness assembly / rear motor high-voltage harness assembly respectively.

Test E: Battery Voltage Family

B111716 Battery voltage too low / B111717 Battery voltage too high: Check battery voltage and on-board charger (OBC) assembly connector → Clear DTCs and retest → Repair according to results → Replace the on-board charger (OBC) assembly.

Key Parameter Quick Reference

Safety Warnings

• This article is for technical reference only. Precision testing of the charging system must be performed by technicians trained and authorized for this vehicle model; high-voltage interlock troubleshooting must follow high-voltage safety procedures, and shorting the interlock circuit is strictly prohibited.
• Before disconnecting connectors for measurement, confirm the vehicle is in the power-down state; battery voltage measurements must follow low-voltage procedures.
• DCAC inverter insulation detection fault (P13061A) and residual voltage protection (P13061C) point to internal assembly issues; replace components according to the procedure and retest.

Maintenance Insights

The most practical part of this charging precision test is the "water pump dual-chain point-to-point" approach: The troubleshooting sequence for OBC over-temperature codes is coolant level → seven leak checks → power (FCR14-3/RCR10-3 battery voltage) → ground (terminal 2 <1Ω) → replace water pump → replace OBC—each of the two water pumps is checked on both "power + ground" lines, voltage verifies power, continuity verifies ground; only after replacing the water pump and still over-temperature does the OBC itself become the suspect, avoiding direct assembly replacement. The convergence logic for Groups B and C is more direct: Input undervoltage/overvoltage/frequency/overcurrent and output undervoltage/overvoltage/overcurrent/short circuit all first check the "power supply equipment" before replacing the OBC—because the primary suspect for these codes is external power supply quality, not the assembly itself. The interlock family follows the same approach as the vehicle-wide precision test (short to ground/short to power/open circuit), but the scope is limited to fast-charge socket + battery pack rear harness + rear motor harness—three charging-related circuits. Finally, note two details: P13061A insulation detection and P13061C residual voltage protection in the DCAC inverter family are discharge-mode-specific codes—they only appear during vehicle-to-load (V2L) discharge; battery voltage too high/low (B111717/16) also ultimately converges to replacing the OBC—because the DC-DC converter inside the OBC is the main power source on the low-voltage side.

---

【This article is for reference only】