CAN Communication System - Lost Communication with Gateway Module (Power Management2)
NETWORKING: CAN COMMUNICATION SYSTEM: U1002, U0164: Lost Communication with Gateway Module (Power Management2)
U0164 - Lost Communication with A/C ECU
DESCRIPTION
* The power management control ECU will store this DTC when no signals can be received from the ECUs that have been memorized as those that are connected to the power management bus.
* When the power management control ECU receives a response signal from the ECUs connected to the power management bus, the power management control ECU recognizes and memorizes that the ECU is connected to the power management bus. Based on this memorized data, the power management control ECU monitors for malfunctions in the ECUs connected to the power management bus when communicating with those ECUs. If the power management control ECU cannot receive response signals from the ECUs that have been memorized as those connected to the power management bus, the power management control ECU determines that a malfunction exists.
HINT
The diagnosis procedure is for when DTC U0164 and U1002 are output by the power management control ECU (Techstream display: Power Management2).
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
* Turn the power switch off before measuring the resistances between CAN bus main wires and between CAN bus branch wires.
* Turn the power switch off before inspecting CAN bus wires for a ground short.
* After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.
* Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.
HINT
* Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
* Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.
PROCEDURE
1. CHECK POWER MANAGEMENT BUS
(a) Turn the power switch off.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(c) Disconnect the cable from the negative (-) battery terminal.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
B -- CHECK FOR OPEN IN CAN BUS WIRE (POWER MANAGEMENT CONTROL ECU)
C -- CHECK FOR SHORT IN CAN BUS WIRES (POWER MANAGEMENT CONTROL ECU)
D -- CHECK FOR SHORT IN CAN BUS WIRE (POWER MANAGEMENT CONTROL ECU)
A -- Continue to next step.
2. CHECK ECU POWER SOURCE CIRCUIT (AIR CONDITIONING AMPLIFIER)
(a) Check the air conditioning amplifier IG power source circuit IG Power Source Circuit.
OK:
Air conditioning amplifier power source circuit is normal.
NG -- REPAIR POWER SOURCE CIRCUIT (AIR CONDITIONING AMPLIFIER)
OK -- Continue to next step.
3. CHECK DTC OUTPUT
(a) Clear the DTCs.
(b) Turn the power switch off.
(c) Turn the power switch on (IG), recheck the DTC.
Result:
B -- GO TO CIRCUITS INDICATED BY OUTPUT DTCS
A -- REPLACE POWER MANAGEMENT CONTROL ECU Removal
4. CHECK FOR OPEN IN CAN BUS WIRE (POWER MANAGEMENT CONTROL ECU)
(a) Disconnect the power management control ECU connector.
Text in Illustration
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- CHECK FOR OPEN IN CAN BUS WIRE (AIR CONDITIONING AMPLIFIER)
OK -- REPLACE POWER MANAGEMENT CONTROL ECU Removal
5. CHECK FOR OPEN IN CAN BUS WIRE (AIR CONDITIONING AMPLIFIER)
(a) Reconnect the power management control ECU connector.
(b) Disconnect the air conditioning amplifier connector.
Text in Illustration
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (POWER MANAGEMENT CONTROL ECU - AIR CONDITIONING AMPLIFIER)
OK -- REPLACE AIR CONDITIONING AMPLIFIER Removal
6. CHECK FOR SHORT IN CAN BUS WIRES (POWER MANAGEMENT CONTROL ECU)
(a) Disconnect the power management control ECU connector.
Text in Illustration
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- CHECK FOR SHORT IN CAN BUS WIRES (AIR CONDITIONING AMPLIFIER)
OK -- REPLACE POWER MANAGEMENT CONTROL ECU Removal
7. CHECK FOR SHORT IN CAN BUS WIRES (AIR CONDITIONING AMPLIFIER)
(a) Reconnect the power management control ECU connector.
(b) Disconnect the air conditioning amplifier connector.
Text in Illustration
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (POWER MANAGEMENT CONTROL ECU - AIR CONDITIONING AMPLIFIER)
OK -- REPLACE AIR CONDITIONING AMPLIFIER Removal
8. CHECK FOR SHORT IN CAN BUS WIRE (POWER MANAGEMENT CONTROL ECU)
(a) Disconnect the power management control ECU connector.
Text in Illustration
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Inspection for CAN Ground Short
Inspection for CAN +B Short
HINT
It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Power Management Bus inspection.
NG -- CHECK FOR SHORT IN CAN BUS WIRE (AIR CONDITIONING AMPLIFIER)
OK -- REPLACE POWER MANAGEMENT CONTROL ECU Removal
9. CHECK FOR SHORT IN CAN BUS WIRE (AIR CONDITIONING AMPLIFIER)
(a) Disconnect the air conditioning amplifier connector.
Text in Illustration
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Inspection for CAN Ground Short
Inspection for CAN +B Short
HINT
It is only necessary to perform the inspection in the above table for the result (short circuit) that was obtained in the Check Power Management Bus inspection.
NG -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (POWER MANAGEMENT CONTROL ECU - AIR CONDITIONING AMPLIFIER)
OK -- REPLACE AIR CONDITIONING AMPLIFIER Removal