P0720 on Chrysler: How to Diagnose & Fix
Output Speed Sensor Circuit Malfunction
1 Chrysler model · 1 documented issue · 1 critical · $200-$1,500 repair
P0720 on Chrysler by model: symptoms, diagnosis and fix
The LeBaron uses the Chrysler A604 (41TE) 4-speed electronically-controlled automatic transaxle. This was one of the first fully electronic automatics and its solenoid pack is the primary failure point. The solenoids develop internal leaks and electrical failures, causing erratic shifting, no-shift conditions, and limp mode (locked in 2nd gear). The transmission controller can also fail. The A604 was so problematic that Chrysler extended warranty coverage on early units.
Common Symptoms
- Transmission stuck in 2nd gear (limp mode)
- Check engine light with P0700 and P07XX codes
- Harsh or erratic shifting between all gears
- No upshift from 2nd gear
- Transmission bangs into gear from Park
How to Fix
Replace the solenoid pack assembly (located in the valve body) with an updated unit. The solenoid pack is accessible by removing the side pan. A remanufactured solenoid pack from TransGo or Rostra is $150-250. If the transmission is in limp mode, scan for codes first — many limp mode events are caused by a speed sensor or input/output shaft sensor failure rather than the solenoid pack.
What you need to diagnose it
The repair instructions explicitly call for reading stored codes. Use a scanner that can read the named code families before choosing a repair.The recommended scanner supports these code families; confirm your exact year, model and module coverage before buying.
ANCEL AD310 Classic OBD-II Scanner
Read & clear engine (P) codes
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Reading and clearing the code is DIY work. Module replacement or reprogramming is not — most modules are VIN-programmed, so a new one does nothing until a shop codes it to your car. Check for an open recall or service bulletin before buying anything.
Sources for this issue (1)
P0720 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0720 mean on a Chrysler?
P0720 stands for "Output Speed Sensor Circuit Malfunction." P0720 indicates a malfunction in the transmission output speed sensor circuit. The output speed sensor measures how fast the transmission's output shaft is turning, which the computer uses to calculate vehicle speed, control shift timing, and manage torque converter lockup. When the signal is missing or implausible, the transmission may shift harshly, get stuck in one gear (limp mode), or the speedometer may read incorrectly. The fault is usually in the sensor, its wiring, or the connector, though internal transmission issues can also be responsible. On Chrysler it is documented across 1 model: LeBaron.
What are the most common causes of P0720?
The most common causes of P0720 are: Failed output (vehicle) speed sensor, Damaged wiring, connector, or corrosion in the sensor circuit, Metal debris on the sensor tip or damaged reluctor ring, Open or short in the signal circuit, Low or contaminated transmission fluid affecting components, Poor ground or reference voltage to the sensor, Faulty transmission control module (TCM/PCM). The specific cause varies by vehicle.
How much does it cost to fix P0720 on a Chrysler?
Published repair estimates on Chrysler range from $200 to $1,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0720 on a different make?
View P0720 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.