Lexus ES: System Voltage Circuit Short to Ground or Open (P056014)
DESCRIPTION
The battery supplies electricity to the ECM even when the engine switch is off. This power allows the ECM to store data such as DTC history and freeze frame data. If the battery voltage falls below a minimum level, the stored ECM data will be cleared and the ECM will determine that there is a malfunction in the power supply circuit. The next time the engine is started, the ECM will illuminate the MIL and store this DTC.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory | Note |
|---|---|---|---|---|---|---|
| P056014 | System Voltage Circuit Short to Ground or Open | ECM back-up power source circuit voltage is low for 3 seconds or more (1-trip detection logic). |
| Comes on | DTC stored | SAE Code: P0562 |
HINT:
If DTC P056014 is stored, the ECM will not store other DTCs.
MONITOR STRATEGY
| Related DTCs | P0562: ECM system voltage/Range check (Low voltage) |
| Required sensors/components (Main) | ECM |
| Required sensors/components (Sub) | - |
| Frequency of operation | Continuous |
| Duration | 3 sec. |
| MIL operation | Immediate |
| Sequence of operation | None |
TYPICAL ENABLING CONDITIONS
| The monitor will run whenever the following DTCs are not stored | None |
| Battery voltage | 8 V or more |
| Engine switch | On (IG) |
| Starter | OFF |
TYPICAL MALFUNCTION THRESHOLDS
| Continuous battery voltage | Less than 3.5 V |
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.
Click here
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- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG) and turn the Techstream on.
- Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
- Turn the engine switch off and wait for 2 minutes or more.
- Turn the engine switch on (IG) and turn the Techstream on.
-
Wait for 3 seconds or more with the engine switch on (IG). [*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: P056014.
-
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.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- Inspect the fuses for circuits related to this system before performing the following procedure.
-
Perform the universal trip to clear permanent DTCs.
Click here
-
Perform registration and/or initialization when parts related to the automatic transaxle are replaced.
Click here
PROCEDURE
| 1. | INSPECT BATTERY |
(a) Check that the battery is not depleted.
Click here
OK:
Battery is not depleted.
| NG |  | CHARGE OR REPLACE BATTERY |
|
| 2. | CHECK BATTERY TERMINAL |
(a) Check that the battery terminals are not loose or corroded.
OK:
Battery terminals are not loose or corroded.
| NG | | REPAIR OR REPLACE BATTERY TERMINAL |
|
| 3. | CHECK TERMINAL VOLTAGE (POWER SOURCE OF ECM) |
| (a) Disconnect the A25 ECM connector. |
|
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A25-1 (BATT) - Body ground | Always | 11 to 14 V |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - ECM) |
|
| 4. | CHECK WHETHER DTC OUTPUT RECURS (DTC P056014) |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs.
Powertrain > Transmission > Clear DTCs(e) Turn the engine switch off and wait for at least 30 seconds.
(f) Turn the engine switch on (IG).
(g) Turn the Techstream on.
(h) Wait 5 seconds or more.
(i) Enter the following menus: Powertrain / Transmission / Trouble Codes.
Powertrain > Transmission > Trouble Codes(j) Read the DTCs.
| Result | Proceed to |
|---|---|
| DTC P056014 is output | A |
| DTCs are not output | B |
| B | | CHECK FOR INTERMITTENT PROBLEMS |
|
| 5. | REPLACE ECM |
(a) Replace the ECM.
Click here
| NEXT | | PERFORM REGISTRATION |
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