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DTC P3052, P3054, Or P3056: DC/DC Converter Actuator Voltage
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P3052
DC/DC Converter Actuator Voltage Sensor Circuit 2 Low Voltage
DTC P3054
DC/DC Converter Actuator Voltage Sensor Circuit 2 High Voltage
DTC P3056
DC/DC Converter Actuator Voltage 2 Performance
Diagnostic Fault Information
Device Voltage Output 1
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
Control
B1445D 0B,
P3052
B144D 04 P3054 P3056
Circuit/System Description
The power supply transformer is used to boost battery voltage to sensitive loads during engine restart. It
provides two voltage outputs that provide the boosted voltage. The power supply transformer
communicates to the ECM. When the engine is not cranking, the power supply transformer passes
through voltage from the two supply circuits. The ECM receives data about the sensed output voltages
provided by the power supply transformer.
Diagnostic Aids
If P3056 is set, verify ECM and T19 Power Supply Converter grounds are clean and tight.
Verify all devices powered by the T19 Power Supply Transformer are operating properly.
B+ circuit 8 supplies voltage to output circuit 9. B+ circuit 11 supplies voltage to output circuit 10.
Conditions For Running The DTC
Ignition ON
Conditions For Setting The DTC
P3052
The ECM detects the DC/DC converter actuator voltage 1 is less than 1 V.
YMMS: Oct 7, 2020
Engine: 1.5L Eng License:
VIN: Odometer:
2016 Chevrolet Malibu LS
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P3054
The ECM detects the DC/DC converter actuator voltage 1 is greater than 28 V.
P3056
The ECM detects the difference between the ECM IGN voltage and DC/DC converter output is greater
than or equal to 1 V.
Action Taken When The DTC Sets
DTC P3052, P3054 and P3056 are type B DTCs
Conditions For Clearing The DTC
DTC P3052, P3054 and P3056 are type B DTCs
Reference Information
Schematic Reference
Starting and Charging Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEWS - INDEX
Description and Operation
Stop/Start System Description and Operation (with KL9)
Electrical Information Reference
Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (LFV or LTG)Powertrain Diagnostic Trouble
Code (DTC) Type Definitions (LKN)
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
NOTE: Use schematics to determine which devices are
powered up on the T19 Power Supply Transformer B+ supply
circuit terminal 10 X1.
1. Ignition OFF, measure and record the battery voltage at the battery terminals.
2. Verify the battery voltage stabilizes between 12.4 and 12.8 V within a few minutes of turning the
ignition OFF.
1. If battery voltage is less than 12.4 V or more than 12.8 V
Refer to Battery Inspection/Test.
1. If battery voltage is between 12.4 and 12.8 V
3. Verify ECM ground is clean and tight.
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4. Engine running, headlights ON, measure and record the battery voltage at the battery terminals.
5. Verify the voltage is at least 1 V greater than the voltage measured in step 1, but less than 15 V.
1. If the voltage is not at least 1 V greater than the voltage measured in step 1 or is greater
than 15 V.
Refer to Charging System Test.
1. If the voltage is at least 1 V greater than the voltage measured in step 1, but less than 15
V.
6. Ignition ON.
7. Verify that the appropriate devices controlled by the T19 Power Supply Transformer control circuit
terminal 10 X1 turn ON when cycling the ignition ON.
1. If the devices do not turn ON
Refer to Circuit/System Testing.
1. If the devices turn ON
8. Verify DTC P3052, P3054 or P3056 does not set.
1. If the DTC sets
Refer to Circuit/System Testing.
1. If the DTC does not set
9. All OK.
Circuit/System Testing
NOTE: You must perform Circuit/System Verification before
Circuit/System Testing.
1. Ign Off and all vehicle systems OFF, disconnect harness connector at T19 Power Supply
Transformer. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 ohms between each circuit ground terminal at the T19 Power Supply
Transformer listed below and ground:
1. Terminal 7
2. Terminal 12
3. Disconnect harness connector at the K20 Engine Control Module.
4. Test for less than 5 Ω between each ground circuit terminal and ground.
1. If 5 Ω or greater
1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
1. If 2 Ω or greater, repair the open/high resistance in the circuit.
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1. If less than 2 Ω, repair the open/high resistance in the ground connection.
1. If less than 5 Ω
5. Verify a test lamp illuminates between each of the B+ circuits at the T19 Power Supply Transformer
listed below and ground:
1. Terminal 8
2. Terminal 11
1. If the test lamp does not illuminate
1. Ignition OFF, remove the test lamp, remove appropriate fuses.
2. Test for infinite resistance between the B+ circuit and ground.
1. less than infinite resistance, repair the short to ground on the circuit.
1. If infinite resistance
3. Test for less than 2 Ω in the B+ circuit end to end.
1. If 2 Ω or greater, repair the open/high resistance in the circuit.
1. If less than 2 Ω, replace the T19 Power Supply Transformer.
1. If the test lamp illuminates
6. Ignition ON.
7. Verify a test lamp illuminates between each of the Ign circuits at the T19 Power Supply Transformer
listed below and ground:
1. Terminal 4
2. Terminal 6
1. If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF, remove the test lamp.
2. Test for less than 2 Ω in the ignition circuit end to end.
1. If 2 Ω or greater, repair the open/high resistance in the circuit.
2. If less than 2 Ω, verify the fuse is OK and there is voltage at the fuse.
1. If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF, remove the test lamp.
2. Test for infinite resistance between the ignition circuit and ground.
1. If less than infinite resistance, repair the short to ground on the circuit.
2. If infinite resistance, replace the T19 Power Supply Transformer.
1. If the test lamp illuminates
8. Ignition Off. Reconnect T19 Power Supply Transformer.
9. Clear codes and operate vehicle in conditions for an autostop.
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10. Verify DTC P3052, P3054, or P3056 does not set.
1. If any of the DTCs are set
If DTC sets, replace T19 Power Supply Transformer.
1. If none of the DTCs are set
11. All OK
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Multifunction Power Supply Converter Replacement for T19 Power Supply Transformer replacement
Control Module References for control module replacement, programming, and setup
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