2020 Honda Accord 2.0t Transmission Codes & Gear Shifting Issue

You’ve got a transmission/drivetrain problem. With those P1715 / P0805 codes and it hanging after 2–3, my working hypothesis is a fault with the two‑way clutch actuator valve stroke sensor or its wiring, not just low fluid. Runner‑up is an internal harness/connector issue inside the trans. A bad TCM is possible but way lower on the list unless all the hardware checks clean.

Most likely culprits

• Two‑way clutch actuator valve stroke sensor fault – Both codes are for that sensor (A/B short and correlation), fits the “won’t shift” and comes back even after fluid service.
• Wiring/connector issue to that sensor (internal harness) – Short to ground/power or high resistance will throw the same codes and kill shift strategy.
• TCM logic/software or failed TCM – Less common, but if sensor and wiring test perfect and fluid is right, TCM or its calibration becomes suspect.

How to narrow it down

1. Confirm fluid level and type the Honda way

   • Use Honda ATF DW‑1 only, check level at the correct temp with the car level, engine running, per service procedure.
   • If level is off or fluid is wrong/burnt, fix that first. If level and type are correct and it still won’t shift and codes return, move on.

2. Clear codes and see what comes back immediately

   • With a good scan tool, clear all TCM codes, then key ON, engine OFF, don’t drive yet.
   • If P1715/P0805 pop back instantly, that points to a hard electrical fault (sensor or wiring), not a mechanical clutch issue.

3. Visual/connector check at the transmission

   • Key off, battery disconnected. Pull the main trans connector and inspect for:
     • Green/white corrosion, bent pins, fluid intrusion, damaged insulation.
   • Clean and reseat. If you see obvious corrosion or fluid in the connector, that’s a big clue wiring/harness is your problem.

4. Ohm/continuity test of the sensor circuit

   • Using a wiring diagram, back‑probe from the TCM connector to the trans connector pins for the two‑way clutch actuator valve stroke sensor.
   • You’re looking for:
     • Proper resistance across the sensor (compare to spec – if you don’t have spec, you’re going to need a shop or service info).
     • No short to ground or power on either signal wire.
   • If resistance is way off or shorted, sensor/harness is bad. If open or intermittent when you wiggle the harness, that’s your harness.

5. Live data check – sensor plausibility

   • With a capable scan tool, look at the two‑way clutch actuator valve stroke sensor A/B data while in Park/Neutral and gently shifting through ranges.
   • If one channel is dead or the two don’t track each other at all, that matches your A/B correlation code and points right at the sensor or its wiring.

6. Check for software updates / TCM relearn

   • On these newer Hondas, TCM updates and clutch learn procedures matter.
   • Dealer or a shop with Honda software can check for updated calibration and perform a clutch/shift relearn.
   • If after fixing any wiring/sensor issue it still acts up, this is the next step before condemning the TCM.

7. Only then consider TCM or internal transmission

   • If:
     • Fluid is correct,
     • Connectors are clean,
     • Sensor and harness ohm out good,
     • Live data looks wrong but hardware tests good,
   • Then you’re in TCM or internal hydraulic/mechanical territory. That’s dealer/trans shop level – not something to guess at.

Possible parts (if needed)

• Two‑way clutch actuator valve stroke sensor (or the valve body assembly if Honda sells it that way).
• Automatic transmission internal wire harness (if continuity/short tests fail).
• Transmission control module (TCM) – only after everything else is proven good and software is current.

A few questions

1. Did these codes show up before you found the fluid low, or only after it started not shifting past 2/3?
2. Do the codes come back immediately after clearing, or only after you try to drive it?
3. Has any work been done on the transmission or wiring recently (accident, engine work, rodent damage, etc.)?

Answer those and I can tighten up whether you’re more likely looking at a sensor/harness job or if it’s time to get a dealer‑level scan and possibly a valve body/TCM involved.

Your mechanic is jumping to “replace the whole transmission” way too fast based on what you’ve shown.

Those codes in your picture:

• P1715 – Two‑Way Clutch Actuator Valve Stroke Sensor A/B Short (Current)
• P0805 – Two‑Way Clutch Actuator Valve Stroke Sensor A/B Correlation (History)

That’s an electrical/sensor problem in the transmission control system, not a generic “trans is worn out” code.

At 160,000 km, a bad transmission is possible, but with specific clutch actuator sensor codes, the smart order is:

1. Rule out wiring / sensor / valve body
2. Then talk about replacing the whole unit if the hard parts are actually bad

What I’d do before condemning the transmission

You’ll need a shop that actually understands Honda electronics, not just a “swap the box” place.

1. Confirm fluid is 100% correct

• Honda ATF DW‑1 only, level checked per Honda procedure, engine running, correct temp, car level.
• If that’s already done right, move on.

2. Clear codes and see how they come back

• Clear TCM codes.
• Key ON, engine OFF, don’t move the car.
• If P1715 pops back immediately, that’s a hard electrical fault – sensor or wiring. A worn clutch pack won’t do that.

3. Inspect the external trans connector and harness

• Unplug the main transmission connector.

• Look for:

  • Green/white corrosion
  • Bent pins
  • Fluid inside the connector
  • Chafed wiring near the trans

• Any of that = fix wiring/connector first. Cheap compared to a transmission.

4. Electrical tests (this is where a real tech earns it)

From the TCM connector, they should:

• Check resistance of the two‑way clutch actuator valve stroke sensor circuit against spec.
• Check for short to ground or power on the sensor wires.
• Wiggle test the harness while watching readings.

If resistance is wrong, open, or shorted → sensor or internal harness/valve body, not the whole transmission case and geartrain.

5. Live data check

On a good scan tool, watch:

• Two‑way clutch actuator valve stroke sensor A/B values while shifting through P‑R‑N‑D (foot on brake, wheels chocked).
• If one channel is dead or they don’t track each other → matches your correlation code and again points to sensor/harness/valve body.

When I’d agree the whole transmission is likely toast

I’d only start talking full replacement if:

• Fluid is correct and clean,
• Connectors and wiring test good,
• Sensor/valve body assembly has been checked or replaced and the same codes and no‑shift remain,
• Or there’s clear mechanical evidence (metal in pan, bad noises, no drive in multiple ranges) plus the electrical stuff checks out.

Right now, with what you’ve told me, the most likely failure is in the two‑way clutch actuator valve stroke sensor circuit or valve body, not the entire transmission.

What I’d tell you to do next

1. Get a second opinion at a Honda‑savvy shop or dealer

Tell them exactly:

• “2020 Accord 2.0T, codes P1715 current and P0805 history, stuck after 2–3. Fluid corrected. I want the two‑way clutch actuator valve stroke sensor circuit and valve body properly diagnosed before anyone calls the whole transmission bad.”

2. Ask them to document:

• Connector condition (photos if possible)
• Ohm/continuity readings on the sensor circuit
• Live data for the actuator stroke sensor A/B

If they can show you:

• Wiring and connector are clean and in spec
• Sensor/valve body is bad and not sold separately from the trans
• Or they’ve replaced the valve body/sensor and it still has the same issue

…then a full transmission starts to make sense.

But based on just those codes and mileage, I would not authorize a full transmission swap yet.

If you can, tell me:

• Did the shop drop the pan or check for metal/debris?
• Does it make any grinding/whining noises, or just refuses to shift?
• Do the codes come back instantly after clearing, or only after driving?

That’ll help narrow whether you’re more in electrical/valve body territory or truly internal mechanical.