Toyota Tacoma 2015-2018 Service Manual: Communication Error from ECM to VSC (P1631)

Toyota Tacoma 2015-2018 Service Manual / Cruise Control / Dynamic Radar Cruise Control System(for 2tr-fe) / Communication Error from ECM to VSC (P1631)

DESCRIPTION

The ECM sends signals such as A/T information signals, dynamic radar cruise control operation signals, brake operation demand signals, and buzzer operation demand signals to the skid control ECU (brake actuator assembly) when the dynamic radar cruise control is operating. Therefore, if the skid control ECU (brake actuator assembly) detects a communication error with the ECM, it sends a malfunction signal back to the ECM.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
P1631	Communication Error from ECM to VSC	While the vehicle speed is 36 km/h (22 mph) or more and the dynamic radar cruise control system is operating, the ECM continuously receives a logical error signal from the skid control ECU (brake actuator assembly) for approximately 1 second or more.	CAN communication circuit ECM Skid control ECU (brake actuator assembly)

CAUTION / NOTICE / HINT

NOTICE:

Before replacing the ECM, refer to Registration.
w/o Smart Key System: Click here

w/ Smart Key System: Click here
First check the CAN communication system by following How to Proceed with Troubleshooting. After checking that there are no malfunctions in the CAN communication system, proceed with troubleshooting.
Click here

PROCEDURE

1.	CHECK CAN COMMUNICATION SYSTEM

(a) Using the Techstream, check if the CAN communication system is functioning normally.

Click here

Result	Proceed to
CAN communication system DTCs are not output	OK
CAN communication system DTCs are output	NG

GO TO CAN COMMUNICATION SYSTEM

2.	CHECK FOR DTCs (RADAR CRUISE1)

(a) Clear the DTCs.

Click here (b) Perform the following to make sure that the DTC detection conditions are

(b) Perform the following to make sure that the DTC detection conditions are met.

HINT:

If the detection conditions are not met, the malfunction cannot be detected.

Turn the ignition switch to ON.
Turn the dynamic radar cruise control system on using the cruise control main switch (ON-OFF button).
Drive the vehicle at 36 km/h (22 mph) or more for 1 second or more.

Click here

Result	Proceed to
DTC P1631 is not output	A
DTC P1631 is output	B

USE SIMULATION METHOD TO CHECK

3.	REPLACE ECM

(a) Replace the ECM.

Click here

4.	CHECK FOR DTCs (RADAR CRUISE1)

(a) Clear the DTCs.

Click here (b) Perform the following to make sure that the DTC detection conditions are

(b) Perform the following to make sure that the DTC detection conditions are met.

HINT:

If the detection conditions are not met, the malfunction cannot be detected.

Turn the ignition switch to ON.
Turn the dynamic radar cruise control system on using the cruise control main switch (ON-OFF button).
Drive the vehicle at 36 km/h (22 mph) or more for 1 second or more.

Click here

Result	Proceed to
DTC P1631 is not output	A
DTC P1631 is output	B

END

REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)

Brake System (P1578)

DESCRIPTION This DTC is stored when a malfunction is detected in the vehicle stability control system. Check the vehicle stability control system when DTC P1578 is stored. DTC No. ...

Vehicle Information Not Obtained (C1A02)

DESCRIPTION When a new millimeter wave radar sensor assembly is installed, it receives vehicle specification information (destination, steering wheel position, 2WD or 4WD, etc.) from the main bod ...

Other materials:

Front Occupant Classification Sensor LH Collision Detection (B1785)
DESCRIPTION DTC B1785 is set when the occupant detection ECU receives a collision detection signal, which is sent by the occupant classification sensor front LH when an accident occurs. DTC B1785 is also set when the front seat with adjuster frame assembly RH is subjected to a strong impact, ...

Theft Deterrent System is not Unset when Engine is Running
DESCRIPTION The theft deterrent system is unset when the IG signal and engine speed signal are input to the main body ECU (multiplex network body ECU) for 2 seconds or more continuously. The engine speed signal is sent from the ECM to the main body ECU (multiplex network body ECU). For this ...

Diagnosis System
DIAGNOSIS SYSTEM DIAGNOSIS FUNCTION (a) The diagnosis function turns off the cruise control indicator, illuminates the master warning light and displays a warning message when a malfunction is detected. When a malfunction is detected in the dynamic radar cruise control system, DTCs are store ...