Toyota Yaris: Charging System / Lost Communication with Alternator Missing Message (P161A87)

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual / Power Source & Network / G16e-gts (battery / Charging) / Charging System / Lost Communication with Alternator Missing Message (P161A87)

DESCRIPTION

The ECM communicates with the generator assembly via LIN communication. If a LIN communication error is detected, the ECM stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Note

P161A87

Lost Communication with Alternator Missing Message

Generator assembly or ECM communication stops for approximately 17 minutes or more with the ignition switch ON

(1 trip detection logic)

  • Wire harness or connector
  • Generator assembly
  • ECM

Comes on

SAE Code: P161A

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.
  • Before replacing the ECM, refer to Service Bulletin.

PROCEDURE

1.

CHECK CHARGING SYSTEM

Click here

NG

REPAIR OR REPLACE CHARGING SYSTEM

OK

2.

CHECK HARNESS AND CONNECTOR (ECM - GENERATOR ASSEMBLY)

(a) Disconnect the D104 ECM connector.

(b) Disconnect the D53 generator assembly connector.

(c) Disconnect the O68 battery state sensor assembly connector.

(d) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

O68-2 (LIN) or D53-2 (LIN) - D104-62 (LIN)

Always

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

O68-2 (LIN), D53-2 (LIN) or D104-62 (LIN) - Body ground

Ignition switch off

(while LIN communication stopped)

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

CLEAR DTC

(a) Check for DTCs using the GTS, and then write them down.

Powertrain > Engine > Trouble Codes

(b) Clear the DTCs.

Powertrain > Engine > Clear DTCs
NEXT

4.

CHECK DTC OUTPUT

(a) Start the engine.

(b) Allow the engine to idle for approximately 17 minutes or more.

(c) Using the GTS, check for DTCs.

Powertrain > Engine > Trouble Codes

Result

Proceed to

Only P161A87 is output

A

P161A87 and P162B87 are output

B

DTCs are not output

C

A

REPLACE GENERATOR WITH REGULATOR ASSEMBLY

B

REPLACE ECM

C

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