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 P0815: Short in Transmission Gear Selection Switch Upshift Switch Circuit, or Transmission Gear Selection Switch Upshift Switch Stuck ON
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review General Troubleshooting Information (see GENERAL TROUBLESHOOTING INFORMATION ).
- This code is caused by an electrical circuit problem and cannot be caused by a mechanical problem in the transmission.
- Turn the ignition switch to ON (II).
- Shift to P.
- Check the Upshift Switch signal input with the HDS in the A/T data list.
Is the Upshift Switch ON?
YES - Go to step 4.
NO - Intermittent failure, the system is OK at this time. Check the S-UP (BLU) wire for an intermittent short to ground between the transmission gear selection switch and the PCM.
- Turn the ignition switch to LOCK (0).
- Disconnect the transmission gear selection switch/ park pin switch/A/T gear position indicator panel light connector at the shift lever bracket.
- Turn the ignition switch to ON (II).
- Check the transmission gear selection switch upshift switch signal input with the HDS in the A/T data list.
Is the Upshift Switch ON?
YES - Go to step 8.
NO - Replace the transmission gear selection switch (see TRANSMISSION GEAR SELECTION SWITCH TEST ), then go to step 19.
- Turn the ignition switch to LOCK (0).
- Jump the SCS line with the HDS.
- Disconnect PCM connector A (49P).
- Check for continuity between transmission gear selection switch/park pin switch/A/T gear position indicator panel light connector terminal No. 7 and body ground.Fig 1: Identifying Continuity Between Transmission Gear Selection Switch Connector Terminal 7 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES - Repair short in the wire between PCM connector terminal A36 and the transmission gear selection switch, then go to step 19.
NO - Go to step 12.
- Reconnect all connectors.
- Update the A/T software in the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see HOW TO SUBSTITUTE THE PCM ).
- Start the engine in P, wait at least 10 seconds, then shift to M.
- Push the shift lever toward the upshift position (+) slowly, and release it; repeat this test 10 times or more.
- Pull the shift lever toward the downshift position (-) slowly, and release it; repeat this test 10 times or more.
- Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0815 indicated?
YES - If the PCM was updated, substitute a known-good PCM (see HOW TO SUBSTITUTE THE PCM ), then recheck. If the PCM was substituted, go to step 1.
NO - Go to step 18.
- Monitor the OBD STATUS for P0815 in the DTCs/ Freeze Data in A/T Mode Menu for a pass/fail.
Does the HDs indicate PASSED?
YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ). If any other DTCs were indicated on step 17, go to the INDICATED DTC'S TROUBLESHOOTING .
NO - If the HDS indicates FAILED, check for poor connections and loose terminals at the transmission gear selection switch and the PCM. If the PCM was updated, substitute a known-good PCM (see HOW TO SUBSTITUTE THE PCM ), then recheck. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, return to step 14 and recheck.
- Clear the DTC with the HDS.
- Start the engine in P, wait at least 10 seconds, then shift to M.
- Push the shift lever toward the upshift position (+) slowly, and release it; repeat this test 10 times or more.
- Pull the shift lever toward the downshift position (-) slowly, and release it; repeat this test 10 times or more.
- Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0815 indicated?
YES - Check for poor connections and loose terminals at the transmission gear selection switch and the PCM, then go to step 1.
NO - Go to step 24.
- Monitor the OBD STATUS for P0815 in the DTCs/ Freeze Data in A/T Mode Menu for a pass/fail.
Does the result indicate PASSED?
YES - Troubleshooting is complete. If any other DTCs were indicated on step 23, go to the INDICATED DTC'S TROUBLESHOOTING .
NO - If the HDS indicates FAILED, check for poor connections and loose terminals at the transmission gear selection switch and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, return to step 20 and recheck.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.