DTC P0A94

DTC P0A94 : DC-DC Converter Performance Problem

NOTE: Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016), or How to Troubleshoot the A/T System (2014 2015), or How to Troubleshoot the Fuel and Emissions Systems .

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
P0A94 DC-DC Converter Performance Problem

DTC (PGM-FI)

DTC check

-1. Turn the vehicle to the ON mode.

- 2. Clear the DTC with the HDS.

- 3. Test-drive the vehicle under the auto idle stop system operating condition, and stop the engine using auto idle stop.

NOTE: If the auto idle stop system indicator (amber) comes on and the engine keeps running, go to step 1-4.

- 4. Check for Pending or Confirmed DTCs with the HDS.

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
P16E5 LIN Communication Error (PCM-DC-DC Converter)

Is DTC P16E5 indicated?

YES

Go to the troubleshooting for DTC P16E5 - Refer to: DTC Troubleshooting: P16E5(With Auto Idle Stop System) (2016), or DTC Troubleshooting: P16E5 (2017 2018 2019 2020) .

Go to step 2.

Problem verification

-1. Check for Pending or Confirmed DTCs with the HDS.

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
P0A94 DC-DC Converter Performance Problem

Is DTC P0A94 indicated?

YES

The failure is duplicated. Go to step 3.

Check the fuses in under-dash sub fuse/relay box A and under-dash sub fuse/relay box B. If the fuse(s) is blown, repair a short in the fuse circuit. If it is OK, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the DC-DC converter and the PCM. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

Determine possible failure area (CST line shorted, others)

-1. Check the parameter(s) below with the HDS.

Signal	Threshold		Current conditions
Signal	Values	Unit	Values	Unit
DC-DC CONVERTER CST ERROR	Normal

Do the current condition(s) match the threshold?

YES

Go to step 5.

Go to step 4.

Shorted wire check (CST line)

-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Jump the SCS line with the HDS.

- 3. Disconnect the following connectors.

DC-DC converter connector A (3P)

PCM connector A (51P)

- 4. Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	DC-DC converter connector A (3P): disconnected
	PCM connector A (51P): disconnected
Test point 1	DC-DC converter connector A (3P) No. 2
Test point 2	Body ground

Courtesy of HONDA, U.S.A., INC.

Is there continuity?

YES

Repair a short in the CST wire between the PCM (A2) and the DC-DC converter.

The CST wire is OK. Replace the DC-DC converter . If DTC P0A94 was indicated after DC-DC converter replaced, update the PCM if it does not have the latest software , or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) , then recheck. If DTC P0A94 goes away and the PCM was updated, troubleshooting is complete. If DTC P0A94 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (2016), or PCM Removal and Installation (2014 2015) .

Open wire check (GND line)

-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Disconnect the following connector.

DC-DC converter connector B (5P)

- 3. Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	DC-DC converter connector B (5P): disconnected
Test point 1	DC-DC converter connector B (5P) No. 4
Test point 2	Body ground

Courtesy of HONDA, U.S.A., INC.

Is there continuity?

YES

Go to step 6.

Repair an open in the GND wire between the DC-DC converter and G501.

Determine possible failure area (DC-DC converter input/output lines)

-1. Reconnect DC-DC converter connector B (5P).

- 2. Turn the vehicle to the ON mode.

- 3. Check the parameter(s) below with the HDS.

Signal	Current conditions
Signal	Values	Unit
DC-DC CONVERTER INPUT ERROR 1
DC-DC CONVERTER INPUT ERROR 2
DC-DC CONVERTER OUTPUT ERROR 1
DC-DC CONVERTER OUTPUT ERROR 2

Do these parameters indicate Malfunction?

DC-DC converter input error 1 indicates Malfunction

Go to step 7.

DC-DC converter input error 2 indicates Malfunction

Go to step 9.

DC-DC converter output error 1 indicates Malfunction

Check for +B OUT1 circuit shorted, or aftermarket parts connected to +B OUT1 wire. Repair a short in +B OUT1 circuit or remove the aftermarket parts if needed. If +B OUT1 wire is OK, replace the DC-DC converter .

DC-DC converter output error 2 indicates Malfunction

Check for +B OUT2 circuit shorted, or aftermarket parts connected to +B OUT2 wire. Repair a short in +B OUT2 circuit or remove the aftermarket parts if needed. If +B OUT2 wire is OK, replace the DC-DC converter .

All parameters indicates Normal

DC-DC converter input and output lines are OK. Replace the DC-DC converter .

Fuse check

-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Check the following fuse.

Fuse	No. G1 (30 A)
Location	Auxiliary under-dash fuse box

Is the fuse OK?

YES

Go to step 8.

Check for a short in the +B DC/DC1 IN1 wire between the DC-DC converter and the No. G1 (30 A) fuse, the +B OUT1 wire between the DC-DC converter and the auxiliary under-dash fuse/relay box, and repair it if needed. Also replace the No. G1 (30 A) fuse.

Open wire check (+B DC/DC1 line)

-1. Disconnect the following connector.

DC-DC converter connector B (5P)

- 2. Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	DC-DC converter connector B (5P): disconnected
Test point 1	DC-DC converter connector B (5P) No. 1
Test point 2	Body ground

Courtesy of HONDA, U.S.A., INC.

Is there battery voltage?

YES

The +B DC/DC1 wire is OK. Replace the DC-DC converter . If DTC P0A94 was indicated after DC-DC converter replaced, update the PCM if it does not have the latest software , or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) , then recheck. If DTC P0A94 goes away and the PCM was updated, troubleshooting is complete. If DTC P0A94 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .

Repair an open in the +B DC/DC1 wire between the DC-DC converter and the No. G1 (30 A) fuse in the auxiliary under-dash fuse box.

Fuse check

-1. Check the following fuse.

Fuse	No. G3 (30 A)
Location	Auxiliary under-dash fuse box

Is the fuse OK?

YES

Go to step 10.

Check for a short in the +B DC/DC2 wire between the DC-DC converter and the No. G3 (30 A) fuse, the +B OUT2 wire between the DC-DC converter and the auxiliary under-dash fuse/relay box, and repair it if needed. If the wires are OK, replace the DC-DC converter . Also replace the No. G3 (30 A) fuse.

Open wire check (+B DC/DC2 line)

-1. Disconnect the following connector.

DC-DC converter connector B (5P)

- 2. Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	DC-DC converter connector B (5P): disconnected
Test point 1	DC-DC converter connector B (5P) No. 2
Test point 2	Body ground

Courtesy of HONDA, U.S.A., INC.

Is there battery voltage?

YES

The +B DC/DC2 wire is OK. Replace the DC-DC converter . If DTC P0A94 was indicated after DC-DC converter replaced, update the PCM if it does not have the latest software , or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) , then recheck. If DTC P0A94 goes away and the PCM was updated, troubleshooting is complete. If DTC P0A94 goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (2016), or PCM Removal and Installation (2014 2015) .

Repair an open in the +B DC/DC2 wire between the DC-DC converter and the No. G3 (30 A) fuse in the auxiliary under-dash fuse box.