B1290 on 2013-2020 Ram 1500: Park Assist Sensor Causes and Fixes

What's Unique About the 2013-2020 Ram 1500

For the Ram 1500, particularly the 2019-2020 model years, this code doesn't always point to a bad part. FCA issued Technical Service Bulletin (TSB) #08-047-19 for 2019 models built before April 11, 2019, stating that code B1290 and others could be set erroneously. This was later superseded by TSB #08-082-20, which expanded the diagnosis to include 2020 models. In these cases, the fix is a simple software update for the Park-Tronic System (PTS) module, not a part replacement. A similar software-related issue was noted for 2014 models under TSB 08-071-14 for vehicles built on or before June 14, 2014, where over-sensitivity could cause false detections and set this code. This makes checking for software updates an important early step for both fourth and fifth-generation trucks.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Generation note: This range covers the fourth generation (2013-2018 DS) and the fifth generation (2019-2020 DT) Ram 1500. The fault is common to both, but part numbers for the sensors differ. TSB #08-047-19 and its successor, #08-082-20, regarding a software fix are specific to 2019-2020 (DT) models. TSB #08-071-14 addresses a similar software issue for 2014 (DS) models. The location of the Park Assist Module (PAM) also differs: on 2013-2018 models, it is located behind the driver's side kick panel, near the emergency brake pedal. 🎬 See exactly where the park assist module is hidden here. On 2019-2020 models, the module is located under the driver's side dashboard, closer to the center console area.

Symptoms You May Notice

• "Service Park Assist System" message on the dashboard.
• Park assist system turns itself off or will not activate.
• No beeping or incorrect beeping when approaching objects while parking.
• The park assist indicator light on the switch may be illuminated or flashing.
• System may falsely detect an obstacle and apply the brakes when backing up (on vehicles with ParkSense Active Braking).

Most Likely Causes

1. Obstructed Sensor Face 🔴 High Probability The front bumper sensors are exposed to road grime, snow, ice, and mud, which can block the ultrasonic signal. Heavy rain can also sometimes trigger temporary faults.
   How to confirm: Visually inspect the face of the inner-most sensor on the driver's side front bumper. Clean it thoroughly with a soft cloth and water. Clear the code and see if it returns.
   Typical fix: Clean the sensor face. This costs nothing and is the first step recommended in official service information.
   Est. part cost: $0
2. Faulty Park Assist Sensor #3 🟡 Medium Probability Sensors are electronic components exposed to weather, vibrations, and potential impacts, leading to internal failure over time. Water intrusion from rain or car washes is a common trigger for failure.
   How to confirm: After cleaning, if the code persists, swap Sensor #3 with an adjacent sensor (like #4). Clear the codes with a scanner. If the fault code changes to follow the sensor (e.g., B1291 for sensor #4), the sensor is confirmed bad.
   Typical fix: Replace the faulty park assist sensor. This is a plug-and-play part accessible from under the front bumper, often without removing it. 🎬 Watch: A step-by-step guide to replacing the sensors yourself. The code must be cleared after replacement for the system to re-initialize.
   Est. part cost: $25-$145
3. Software Glitch (2019-2020 Models) ⚪ Low Probability Applies specifically to 2019 Ram 1500s built on or before April 11, 2019, and some 2020 models.
   How to confirm: Check the vehicle's build date. If it falls within the range and exhibits the code, consult a dealer about TSB 08-047-19 or 08-082-20.
   Typical fix: Reprogram the Park-Tronic System (PTS) module with the latest software. This must be done by a dealer or a shop with a wiTECH scan tool.
   Est. part cost: $0 (if under warranty), $185-$295 (dealer labor for flash out of warranty).

Rare But Worth Checking

• Wiring Harness or Connector Damage: The wiring to the front bumper is susceptible to damage from road debris or corrosion. Check the connector and a few inches of wiring leading to Sensor #3 for any visible chafing, breaks, or green/white corrosion. In some cases, the main harness connection to the control module can corrode. Repair pigtails for the sensor connector are available.
• Missing or Improperly Seated Decoupling Ring: Each sensor has a small rubber or plastic ring (isolator) that isolates it from the bumper to prevent false readings from vibration. If this ring is missing or installed incorrectly after a repair, it can cause signal issues. The Mopar part number is typically 04806229AA or 68271824AA.

Diagnosis Steps

1. Read the code with an OBD-II scanner capable of reading Body Control Module (BCM) codes to confirm B1290 is present.
2. Locate Sensor #3: It is the inner sensor on the driver's side of the front bumper.
3. Thoroughly clean the face of Sensor #3 with soap, water, and a soft cloth. Remove all dirt, mud, snow, or ice.
4. Clear the trouble codes using the scanner and test the park assist system. If the code does not return, the problem is solved. Note: The system may not function until the code is cleared.
5. If the code returns, perform a sensor swap. Disconnect and remove Sensor #3 and an adjacent sensor (e.g., Sensor #4, the inner sensor on the passenger side). Install Sensor #3 in position #4 and vice-versa. Access is from behind the bumper.
6. Clear codes and re-test. If the code changes to B1291 (for Sensor 4), the original sensor is faulty and must be replaced.
7. If the code remains B1290 after the swap, the problem is likely in the wiring to that specific location. Inspect the harness and connector for damage, corrosion, or loose pins. Test for power, ground, and signal continuity if you have a multimeter.
8. For 2019-2020 models, if other steps fail, consult a dealer about TSB 08-082-20 for a potential software update. For 2014 models, inquire about TSB 08-071-14.

Parts You'll Likely Need

• Park Assist Sensor (Front) (OEM #1EW63TZZAA (2013-2018), 5YV68TZZAA (2019-2020)) — This is the component that fails most often after ruling out obstructions. Internal electronics can fail from exposure and vibration. Note that OEM sensors come unpainted ('paint as required').
  Trusted brands: Mopar, Dorman, Standard Motor Products (SMP), Bosch, TRQ
  OEM price range: $95-$145
  Aftermarket price range: $25-$75
• Park Assist Sensor Decoupling Ring (OEM #04806229AA or 68271824AA) — This small rubber/plastic isolator ring can be lost or damaged during sensor replacement or a minor bumper impact, causing vibration and signal errors.
  Trusted brands: Mopar
  OEM price range: $5-$10
  Aftermarket price range: $2-$5

Related Codes That Often Appear With This One

• B128E — This is the code for Sensor 1. It can appear with B1290 if multiple sensors are dirty or if a software glitch is affecting the entire system.
• B128F — This is the code for Sensor 2. It can appear with B1290 if multiple sensors are dirty or if a software glitch is affecting the entire system.
• B1291 — This is the code for Sensor 4. It can appear with B1290 if multiple sensors are dirty or if a software glitch is affecting the entire system.

Technical Service Bulletins (TSBs) & Recalls

• 08-242-25: Confirms B1290-25 as PTS Sensor 3-Signal Shape/Waveform Failure.
• 08-047-19: Notes that on 2019 models, B1290-25 may be set erroneously and advises a software update for the PTS module.
• 08-082-20: Supersedes 08-047-19, expanding the software fix to include all 2019-2020 models and is the most current TSB for this issue.
• 9003059: Recommends checking for and cleaning snow/mud/ice from sensors as a first step.
• 08-071-14: Confirms B1290-25 definition for 2014 models and addresses a software fix for over-sensitivity on early 2014 builds.

Platform-Specific Known Issues

• TSB #08-082-20 (superseding #08-047-19) notes that on some 2019-2020 Ram 1500s, this code can be triggered by a software issue and requires a module reprogram instead of a part replacement.
• The sensor numbering system is specific: 1-6 for the front (driver's side outer to passenger side outer) and 8-11 for the rear (passenger side outer to driver's side outer). B1290 is always front driver's side, inner position (#3).

Mechanic-Grade Diagnostic Values

• Park Assist Sensor Supply Voltage — expected: Approx. 8.4-8.5 Volts with key on. Failure: Significantly lower or no voltage indicates an issue with the Park Assist Module (PAM) or the supply circuit.
• Sensor Signal Circuit Resistance to Ground — expected: No continuity (infinite resistance). Failure: Continuity to ground indicates a short in the signal wire.
• Sensor Signal Circuit Resistance (end-to-end) — expected: Less than 5.0 Ohms. Failure: Resistance above 5.0 Ohms indicates an open or high resistance in the signal wire between the sensor and the PAM.
• Working Sensor Ultrasonic Clicking — expected: A faint, rhythmic clicking or buzzing sound from the sensor face when the system is active.. Failure: Silence from a sensor while others are clicking indicates the silent sensor is likely faulty.

Scan Tool Commands That Help

• wiTECH: Reprogram Park Assist Module (PAM) — This function is required to perform the software updates specified in TSBs 08-071-14 and 08-082-20, which can resolve false B1290 codes on affected 2014 and 2019-2020 models.

Wiring & Ground Locations

• Park Assist Module (PAM) - 2013-2018 (DS) — Behind the driver's side kick panel, mounted to the cowl side inner panel, near the emergency brake pedal.. This is the control unit that receives the signal from Sensor #3. Technicians may need to access its connectors to test the wiring continuity from the sensor.
• Park Assist Module (PAM) - 2019-2020 (DT) — Under the driver's side of the dashboard, to the right of the steering column, closer to the center console area.. This is the location for the control module on 5th generation trucks. It must be accessed for software updates or if wiring tests need to be performed at the module side.
• Sensor Connector (Front) — Directly on the back of each park assist sensor, accessible from underneath and behind the front bumper.. This is the primary point for testing voltage, ground, and signal, as well as for performing a sensor swap diagnostic. Corrosion or damage here is a common cause of failure.

Real Owner Repair Stories

• Rain City Wrench YouTube Channel (2012 Ram 1500) — Service Park Assist message, codes B1295, B1296, B1297, B1298 (all four rear sensors shorted to ground).
  ❌ Tried (didn't work) The previous technician had already replaced the Park Assist Module (PAM), but the codes remained.
  ✅ What actually fixed it After testing and finding good power (8.47V) and communication lines to the module, the technician replaced all four rear sensors with aftermarket units. This cleared all the codes and restored system function, indicating a simultaneous failure of all four original sensors.

OEM Part Supersession History

• 1EW63DX8AA, 1EW63LAUAA, etc. → 1EW63TZZAA — This is the base part number for the unpainted sensor used on 2013-2018 Ram 1500s and many other Chrysler vehicles. The various superseded numbers were often for pre-painted sensors corresponding to specific vehicle colors.
  Heads up: 1EW63TZZAA is the correct service replacement for the 4th generation (DS) trucks, but it is not compatible with the 5th generation (DT) trucks (2019+), which use a different sensor (5YV68TZZAA).

Model Year Variations Within This Range

• 2013-2018 (DS) vs 2019-2020 (DT): The Park Assist Module (PAM) is in a different location. On DS models, it's behind the driver's kick panel. On DT models, it's under the dash near the center stack. The sensors themselves also have different part numbers and are not interchangeable between generations.
• 2014 (early builds): TSB 08-071-14 was issued for 2014 models built on or before June 14, 2014, for overly sensitive front sensors causing false detections and setting waveform failure codes like B1290. The fix is a PAM software update, similar to the issue on 2019-2020 models.