P0973 — Shift Solenoid "A" Control Circuit Low

powertrain (engine/transmission)

Is it safe to drive?

Drive with caution Drive only if the transmission still shifts predictably, and avoid highway speeds. Driving with slipping or limp mode accelerates internal wear — every kilometre can add to the final repair bill.

How to diagnose with an OBD scanner

  1. Read the code and freeze frame Connect an OBD2 scanner, confirm P0973 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
  3. Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the automatic transmission control for damage, corrosion, chafing or poor contact.
  4. Subsystem check Check for supply voltage at the shift solenoid "A" control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
  5. Subsystem check Check transmission fluid level and condition — dark, burnt fluid points to internal wear.
  6. Subsystem check Read transmission-specific codes and live data (solenoid states, input/output speed) with a capable scanner.
  7. Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P0973 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P0973 (parts and labor, USD, independent shop rates): Replace a shift solenoid: $300–$800; Transmission rebuild or replacement: $2,500–$5,500; Transmission fluid service: $150–$350; Valve body repair or replacement: $700–$1,500. Overall, fixing P0973 usually costs between $150 and $5,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

How do I diagnose P0973 myself?

Start with a scan: confirm P0973, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the shift solenoid "A" control, and verify the suspect component against live data before buying parts.

What are the symptoms of P0973?

Drivers most often notice: Check Engine or transmission warning light on, transmission stuck in one gear (limp mode), no movement in severe cases, harsh or delayed shifting.

How much does it cost to fix P0973?

Replace a shift solenoid — $300–$800; Transmission rebuild or replacement — $2,500–$5,500; Transmission fluid service — $150–$350; Valve body repair or replacement — $700–$1,500. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

Will P0973 clear itself?

Sometimes P0973 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What is the most common cause of P0973?

The most common causes are: internal mechanical wear (clutches, torque converter), wiring or connector faults in the valve body harness, faulty transmission speed sensor.

When your vehicle's transmission control module logs trouble code P0973, it means one specific electrical condition has been confirmed: the signal circuit for shift solenoid "A" is reading far below its expected voltage range. Think of shift solenoids as the on-off valves that direct transmission fluid pressure to the right clutches at the right moment. They respond to commands from the PCM (powertrain control module), which monitors their operation through a feedback circuit. P0973 fires when that feedback signal stays close to ground potential — essentially telling the computer "this solenoid isn't getting the voltage it needs."

The PCM won't set P0973 after a single bad reading. It runs multiple checks under specific driving conditions before activating the check engine light and storing the code. This "verified fault" approach keeps you from chasing ghost codes triggered by a loose connector or a one-time electrical spike. The module also captures a freeze frame — a snapshot of engine load, RPM, coolant temperature, and vehicle speed at the moment the fault was confirmed. That snapshot is your roadmap for recreating the failure during diagnosis.

What happens next depends on how severely the solenoid circuit is compromised. In mild cases, you might notice only occasional harsh shifts. In severe cases — especially if the PCM puts the transmission into failsafe (limp mode) — the vehicle may refuse to move or stay locked in a single gear. Either way, the underlying issue is electrical: either the solenoid isn't receiving adequate voltage, or the circuit is shorted to ground somewhere between the PCM and the solenoid itself.

Common Symptoms of P0973

  • Check engine or transmission warning lamp illuminated on the dashboard
  • Transmission locked in a single gear (limp-in mode)
  • Complete loss of forward or reverse movement in extreme cases
  • Harsh, jerky, or significantly delayed gear changes
  • Noticeable shuddering or vibration at highway speeds
  • Slipping between gears under load

What Causes P0973?

The most frequent culprits tend to be wiring-related or involve the solenoid itself. In order of likelihood:

  • Failed shift solenoid "A" drawing the circuit voltage down
  • Wiring harness damage (chafed, melted, or cut insulation) causing a direct short to ground
  • Corroded, loose, or damaged connector at the solenoid or transmission harness
  • Missing or intermittent supply voltage to the solenoid circuit
  • Low or severely degraded transmission fluid restricting hydraulic function
  • Faulty transmission input/output speed sensor affecting solenoid command logic
  • Worn valve body (where the solenoid mounts) with internal hydraulic leaks
  • Internal mechanical transmission damage (clutch wear, torque converter issues) — less common but possible with high mileage

How to Diagnose P0973

Accurate diagnosis prevents unnecessary part swapping. Follow this logical sequence:

  1. Connect an OBD2 scanner, retrieve all stored codes, and record the freeze frame data linked to P0973. Note the exact conditions — load, RPM, temperature, speed — so you can replicate them on a test drive.
  2. Research manufacturer TSBs (technical service bulletins) for your specific make, model, and year. Many transmission-related codes have published factory fixes, software updates, or known issues documented by the OEM.
  3. Perform a thorough visual inspection of the transmission wiring harness and connectors. Look for damaged insulation, rubbed-through wires contacting metal, corrosion at pins, or evidence of heat damage near the exhaust.
  4. Test for supply voltage at the solenoid connector with the key on and engine off. Then check resistance from the signal circuit to ground — a reading near zero ohms confirms a short-to-ground in the harness.
  5. Measure shift solenoid "A" resistance with a multimeter and compare to factory specifications. Out-of-spec resistance (typically too low) points to a failed solenoid.
  6. Inspect transmission fluid level and condition. Burnt, dark, or low fluid correlates with internal wear and can contribute to solenoid performance issues.
  7. Clear the code, complete a full drive cycle matching the freeze frame conditions, and verify P0973 does not return.

Repair Options for P0973

Once the root cause is identified, repair costs vary significantly based on what failed:

  • Shift solenoid replacement (parts and labor): $300–$800
  • Valve body repair or replacement (parts and labor): $700–$1,500
  • Transmission fluid service (drain/fill or flush): $150–$350
  • Transmission rebuild or complete replacement (parts and labor): $2,500–$5,500

Always address the cheapest probable causes first — wiring damage and solenoid failure are far more common than full transmission replacement.

Total Repair Cost Summary

Most P0973 repairs fall well below the catastrophic end of the scale. If inspection reveals a failed solenoid, expect to pay roughly $300–$800 for the fix. Wiring harness repairs (if the short is accessible and the harness is repairable) often cost far less than parts replacement. Valve body work typically runs $700–$1,500 depending on whether you opt for repair or outright replacement. Full transmission replacement — the worst-case scenario — can reach $5,500 or more. The overall range for P0973 diagnosis and repair sits between $150 and $5,500, with the majority of cases resolving in the $300–$1,000 range. Proper diagnosis upfront is the single biggest cost saver.

Can You Drive with P0973?

If the transmission still shifts and the vehicle moves normally, short trips on lower-speed roads are acceptable on a limited basis. However, any slipping, shuddering, or limp-mode behavior means stop driving — continued operation accelerates internal wear and can turn a $500 solenoid fix into a $4,000 transmission job. Use caution, prioritize getting it diagnosed, and treat the check engine light as a reminder that the problem won't fix itself.

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