Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0563
DTC P0563 : PCM Power Source Circuit Unexpected Voltage
NOTE: Before you troubleshoot, review the general troubleshooting information .
| DTC Description | Confirmed DTC | Pending DTC | Freeze Frame |
|---|---|---|---|
| P0563 PCM Power Source Circuit Unexpected Voltage |
DTC (PGM-FI)
- Problem verification
-1. Turn the vehicle to the ON mode.
-2. Clear the DTC with the HDS.
-3. Turn the vehicle to the OFF (LOCK) mode.
-4. Wait 10 seconds.
-5. Turn the vehicle to the ON mode.
-6. Check for Pending or Confirmed DTCs with the HDS.
DTC Description Confirmed DTC Pending DTC Freeze Frame P0563 PCM Power Source Circuit Unexpected Voltage Is DTC P0563 indicated?
YES
The failure is duplicated. Go to step 2.
NO
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at PGM-FI main relay 1 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 (FI MAIN RLY CL- line, others)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Jump the SCS line with the HDS.
-3. Disconnect the following connector.
PCM connector A (51P) -4. Measure the voltage between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode PCM connector A (51P): disconnected Test point 1 PCM connector A (51P) No. 7 Test point 2 Body ground Is there battery voltage?
YES
Go to step 5.
NO
Go to step 3.
- Shorted wire check (FI MAIN RLY CL- line)
-1. Remove PGM-FI main relay 1 (A) and the ignition coil relay (B) from the under-hood fuse/relay box.
-2. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode PCM connector A (51P): disconnected PGM-FI main relay 1: disconnected Ignition coil relay: disconnected Test point 1 PCM connector A (51P) No. 7 Test point 2 Body ground Is there continuity?
YES
Repair a short in the FI MAIN RLY CL- wire between the PCM (A7) / PGM-FI main relay 1 and the ignition coil relay.
NO
The FI MAIN RLY CL- wire is OK. Go to step 4.
- Relay check
-1. Test PGM-FI main relay 1 .
Is the relay OK?
YES
Update the PCM if it does not have the latest software, or substitute a known-good PCM , then recheck. If DTC P0563 goes away and the PCM was updated, troubleshooting is complete. If DTC P0563 goes away and the PCM was substituted, replace the original PCM .
NO
Replace PGM-FI main relay 1.
- Shorted wire check (FI MAIN RLY OUT line to power)
-1. Remove PGM-FI main relay 1 (A) from the under-hood fuse/relay box.
-2. Measure the voltage between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode PCM connector A (51P): disconnected PGM-FI main relay 1: disconnected Test point 1 PCM connector A (51P) No. 9 Test point 2 Body ground Is there battery voltage?
YES
Repair a short to power in the FI MAIN RLY OUT wire between the PCM (A9) and PGM-FI main relay 1.
NO
The FI MAIN RLY OUT wire is OK. Go to step 6.
- Relay check
-1. Test PGM-FI main relay 1 .
Is the relay OK?
YES
PGM-FI main relay 1 is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM , then recheck. If DTC P0563 goes away and the PCM was updated, troubleshooting is complete. If DTC P0563 goes away and the PCM was substituted, replace the original PCM .
NO
Replace PGM-FI main relay 1.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.