Toyota Tacoma (2015-2018) Service Manual: Lost Communication with ECM/PCM "A" Missing Message (U010087)
DESCRIPTION
The engine control unit and the transmission control unit are located inside the ECM. The engine control unit intercommunicates with the transmission control unit with the Controller Area Network (CAN).
If there is a problem in this intercommunication, the ECM stores a DTC.
|
DTC Code |
DTC Detection Condition |
Trouble Area |
SAE |
|---|---|---|---|
|
U010087 |
All conditions are met for 1.25 seconds or more (1-trip detection logic): (A) The ignition switch is ON and battery voltage is 9.5 V or higher. (B) There is no communication between the engine control unit and transmission control unit. |
ECM |
U0100 |
MONITOR STRATEGY
|
Related DTCs |
U0100: Verify communication |
|
Required Sensors/Components (Main) |
ECM |
|
Required Sensors/Components (Related) |
- |
|
Frequency of Operation |
Continuous |
|
Duration |
1.25 seconds |
|
MIL Operation |
Immediate |
|
Sequence of Operation |
None |
TYPICAL ENABLING CONDITIONS
|
Monitor runs whenever following DTCs not stored |
None |
|
Battery Voltage |
9.5 V or higher |
|
Ignition Switch |
ON |
|
Starter |
OFF |
TYPICAL MALFUNCTION THRESHOLDS
|
Communication signal |
Lost communication with engine control unit |
CONFIRMATION DRIVING PATTERN
HINT:
- After repairs have been completed, clear the DTCs and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.
- When clearing the permanent DTCs, refer to the Clear Permanent DTC procedure
(See page
.gif)
).
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON and turn the Techstream on.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
- Turn the ignition switch off and wait for 2 minutes or more.
- Turn the ignition switch to ON and turn the Techstream on.
- Wait for 2 seconds or more with the ignition switch to ON. [*1]
HINT:
[*1] : Normal judgment procedure.
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
- Enter the following menus: Powertrain / Transmission / Utility / All Readiness.
- Input the DTC: U010087.
- Check the DTC judgment result.
Techstream Display
Description
NORMAL
- DTC judgment completed
- System normal
ABNORMAL
- DTC judgment completed
- System abnormal
INCOMPLETE
- DTC judgment not completed
- Perform driving pattern after confirming DTC enabling conditions
N/A
- Unable to perform DTC judgment
- Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
HINT:
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE or N/A, perform the normal judgment procedure again.
CAUTION / NOTICE / HINT
NOTICE:
- Perform the universal trip to clear permanent DTCs (See page
).
- Perform registration and/or initialization when parts related to the
automatic transmission are replaced (See page
)
PROCEDURE
|
1. |
CHECK DTC OUTPUT (IN ADDITION TO DTC U010087) |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Transmission / Trouble Codes.
(e) Read the DTCs using the Techstream.
Result|
Result |
Proceed to |
|---|---|
|
Only U010087 is output |
A |
|
U010087 and other DTCs are output |
B |
| A | .gif) |
REPLACE ECM |
| B | |
GO TO DTC CHART |
Transmission Fluid Temperature Sensor "B" Circuit Short to Battery or Open (P274015)
DESCRIPTION
The No. 2 ATF temperature sensor is installed in the transmission valve body
assembly.
If the ECM detects an abnormally high ATF temperature near this sensor, it illuminates
the warn ...
Internal Control Module EEPROM Data Memory Failure (P062F44)
DESCRIPTION
The ECM monitors its internal operation and it will set this DTC when it detects
an internal malfunction.
DTC No.
DTC Detection Condition
Trouble Area
...
Other materials:
Push Switch / Key Unlock Warning Switch Malfunction (B2780)
DESCRIPTION
This DTC is stored if the transponder key ECU assembly does not detect that the
unlock warning switch assembly is ON even when the key is in the ignition key cylinder.
Under normal conditions, the unlock warning switch assembly is ON when the key is
in the ignition key cylinder.
...
Disassembly
DISASSEMBLY
PROCEDURE
1. REMOVE FRONT LICENSE PLATE BRACKET
(a) Remove the 2 screws and front license plate bracket.
2. REMOVE NO. 4 ENGINE ROOM WIRE (w/ Fog Light)
(a) Disconnect the 2 connectors.
...
Problem Symptoms Table
PROBLEM SYMPTOMS TABLE
If a normal code is displayed during the DTC check but the problem still occurs,
check the circuits for each problem symptom in the order given in the table below
and proceed to the relevant troubleshooting page.
NOTICE:
When replacing the skid control ECU (master cylin ...
