P0887 on 2015-2017 Ram ProMaster City: TCM Power Control Circuit High Causes and Fixes

What's Unique About the 2015-2017 Ram PROMASTER CITY

The Ram ProMaster City uses a 9-speed automatic transmission (948TE) that is also found in other FCA vehicles like the Jeep Cherokee and Chrysler 200. This transmission is well-known for having complex software that has required numerous updates to fix drivability and electrical faults. For this specific vehicle, Ram has acknowledged P0887 as a known issue and released Technical Service Bulletins (TSBs), such as 21-018-17 REV. C, indicating the fix is a software calibration update, 🎬 Watch: How a TCM flash update fixes P0887 whining noises. not necessarily a hardware failure. Additionally, a specific recall (S24 / NHTSA 16V-202) was issued for 2015-2016 models due to a poorly-placed CAN-C bus connector under the driver's seat that is prone to moisture and corrosion, directly causing communication loss and this code.

Diagnostic Flowchart

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

Symptoms You May Notice

• Check Engine Light (Malfunction Indicator Lamp) is on
• Transmission warning light on
• Harsh or erratic shifting
• Transmission may get stuck in one gear (limp mode)
• Delayed engagement when shifting from Park to Drive or Reverse
• Vehicle may shift to neutral unexpectedly while driving
• Vehicle may not restart after being turned off

Most Likely Causes

1. Outdated Transmission Control Module (TCM) Software 🔴 High Probability → Shop Transmission Assembly FCA has released multiple Technical Service Bulletins (e.g., #21-018-17 REV. A, REV. C) specifically to address P0887 with a software update. This indicates it's a known calibration issue intended to fix this code and improve overall shift quality.
   How to confirm: A Ram dealer or a qualified shop with a wiTECH scan tool can check the current software calibration ID against the latest version available from the manufacturer's database.
   Typical fix: Reprogramming (flashing) the TCM with the latest available software. The TSB specifies that the PCM should also be updated and a battery charger must be used to maintain stable voltage (13.2-13.5V) during the flash process.
   Est. part cost: $0-$0
2. Corroded CAN-C Bus Connector 🟡 Medium Probability A recall (S24 / NHTSA 16V-202) was issued for 2015-2016 models because the CAN-C 'Star' connector, located under the driver's seat, is susceptible to water intrusion and corrosion. This corrosion disrupts communication with the TCM, causing various codes and symptoms, including P0887.
   How to confirm: Visually inspect the CAN-C 'Star' connector, located under the driver's seat carpet/trim, for any signs of green or white corrosion on the pins. The recall procedure mandates this inspection.
   Typical fix: If corrosion is found, the connector and any damaged pins must be replaced. The recall procedure also involves relocating the connector to a more protected area under the instrument panel to prevent recurrence.
   Est. part cost: $20-$65
3. Wiring Harness or Connector Issue ⚪ Low Probability Beyond the specific CAN-C connector recall, general wiring issues can occur. A weak or failing battery can also introduce fluctuating voltages, potentially triggering 'circuit high' codes, though this is less common than the software or recall issues.
   How to confirm: Visually inspect the wiring harness leading to the TCM for any signs of chafing, breaks, or corrosion. Use a multimeter to check for proper voltage and ground at the TCM connector according to the factory service manual. Test the battery to ensure it provides stable voltage.
   Typical fix: Repair the damaged section of the wiring harness or clean/replace the affected connector. Replace the battery if it fails a load test.
   Est. part cost: $10-$250

Rare But Worth Checking

• Failed Transmission Control Module (TCM): → Shop Transmission Assembly This is typically a last resort. It should only be considered after the software has been confirmed to be up-to-date and all wiring/connector issues (including the S24 recall) have been ruled out. In some cases, a faulty valve body which houses the TCM may be replaced.

Diagnosis Steps

1. Read all Diagnostic Trouble Codes (DTCs) from the PCM and TCM with a compatible scan tool.
2. Enter the vehicle's VIN into the NHTSA or manufacturer database to check for open recalls, specifically Safety Recall S24 / NHTSA 16V-202 for the CAN-C bus connector on 2015-2016 models.
3. Check for applicable Technical Service Bulletins (TSBs). TSB #21-018-17 REV. C directly addresses P0887 with a software update for 2015-2016 models.
4. If a software update is available per the TSB, have a dealer or qualified shop reprogram the TCM and PCM. This is the most likely fix and should be performed before hardware replacement.
5. If the code returns or if specified by Recall S24, inspect the CAN-C bus connector under the driver's seat for water intrusion or corrosion. Repair and relocate the connector as per the recall instructions.
6. If the software is current and no corrosion is found, perform a thorough visual inspection of the wiring harness and connectors going to the TCM.
7. Using a multimeter and the vehicle's wiring diagram, verify that the TCM is receiving the correct voltage and has a solid ground connection. Test the vehicle's battery to rule out voltage stability issues.
8. If all other steps fail to resolve the issue, the TCM itself may be faulty and require replacement. This is the least likely cause.

Parts You'll Likely Need

• TCM Software Reprogramming — This is a service, not a physical part. It is the most common fix documented by Ram in official service bulletins (like 21-018-17 REV. C) to correct this code.
  OEM price range: $150-$300
  Aftermarket price range: N/A
• CAN-C Bus Connector (OEM #68140647AA) — This connector is subject to Recall S24 for corrosion on 2015-2016 models and can cause various transmission communication issues, including P0887.
  Trusted brands: Mopar
  OEM price range: $50-$65
  Aftermarket price range: $30-$50
• Transmission Control Module (TCM) — This is a rare cause, only needed if the module itself has failed internally and does not respond to reprogramming. It is often integrated with the valve body.
  Trusted brands: Mopar
  OEM price range: $600-$900
  Aftermarket price range: $400-$700

Related Codes That Often Appear With This One

• P1720 — Often listed with P0887 in TSBs #21-018-17 REV. A and REV. C related to TCM software updates.
• P1634 — Often listed with P0887 in TSBs #21-018-17 REV. A and REV. C related to TCM software updates.
• P1DCCD — Often listed with P0887 in TSBs #21-018-17 REV. A and REV. C related to TCM software updates.
• P0711 — Often listed with P0887 in TSBs #21-018-17 REV. A and REV. C related to TCM software updates.
• P1DAD — Listed as a related code in TSB #21-018-17 REV. A.
• P1CC9 — Listed as a related code in TSB #21-018-17 REV. A.

Technical Service Bulletins (TSBs) & Recalls

• Bulletin #2101717: Notes that P0887 can be fixed with a software update that also improves gear shifts.
• Bulletin #21-018-17 REV. A: Explicitly lists P0887 as a code fixed by reprogramming the TCM with the latest software on 2015-2016 models.
• Bulletin #21-018-17 REV. C: Supersedes previous versions, confirming the software flash fix for P0887 and other codes, and adds other enhancements for 2015-2016 models.
• Bulletin #21-039-15 REV B: Lists P0887 among other potential transmission-related DTCs.
• Bulletin #2101817: Lists P0887 as a potential DTC for MIL illumination.

Platform-Specific Known Issues

• A recall (S24 / NHTSA 16V-202) was issued for 2015-2016 models because the CAN-C bus connector located under the driver's seat can corrode from water intrusion. This leads to a loss of communication with the TCM, causing the transmission to shift to neutral unexpectedly, a no-start condition, and the P0887 code. The fix involves inspecting, replacing if corroded, and relocating the connector to under the instrument panel.

Mechanic-Grade Diagnostic Values

• Battery Voltage During TCM Flash — expected: Stable voltage between 13.2 and 13.5 volts. Failure: Voltage dropping below 13.2V or climbing above 13.5V can cause the flash to fail or be interrupted.
• TCM Power Supply Voltage (General Operation) — expected: Greater than 10.0 volts. Failure: If battery voltage to the TCM drops below 10.0 volts for 15 seconds, the system may enter limp-in mode. A drop below 7.2 volts for even 200ms can also trigger faults.

Scan Tool Commands That Help

• wiTECH: Reprogram TCM — This is the primary repair procedure for code P0887 as specified by multiple TSBs. It updates the module's software to correct calibration errors.
• wiTECH: Proxy Configuration Alignment — This procedure is required after replacing the TCM or other modules on the CAN bus. It synchronizes all vehicle modules to recognize the new part. Failure to perform a proxy alignment can cause communication errors, a blinking odometer, and prevent the new module from functioning correctly.
• wiTECH: Clear All DTCs — This function is used after the TCM reprogramming is complete. The wiTECH application automatically presents this option. However, TSBs specifically note NOT to clear the shift adaptives in the TCM's memory, as this can cause poor shift quality until the transmission relearns.

Wiring & Ground Locations

• Primary Engine/Transmission Ground Strap — A braided ground strap that connects from the side of the transmission case to a bolt on the top of the driver-side transmission mount. It is visible and accessible after removing the driver-side headlight assembly.. This is the primary ground path for the engine and transmission. A loose, corroded, or broken strap can cause inconsistent voltage and grounding for all related modules, including the TCM, potentially leading to 'circuit high' or other electrical ghost codes.
• TCM Power Relay — Typically located in the under-hood fuse box (Power Distribution Center). The specific relay is labeled for the TCM or transmission.. This relay controls the main power feed to the Transmission Control Module. If the relay's contacts become stuck or 'welded' closed, it can supply constant power to the TCM when it should be off, causing a 'Circuit High' condition.
• CAN-C 'Star' Connector — Under the driver's seat, beneath the carpet and trim (for 2015-2016 models). Recall S24 involves relocating it to under the instrument panel.. This is a central junction for the CAN-C communication network. Corrosion here, as identified in Recall S24, directly interrupts communication between the TCM and other modules, causing P0887 and other transmission faults.

Real Owner Repair Stories

• promasterforum.com user 'drt-r' (2017 Ram ProMaster City) — Check engine light on, transmission stuck in 3rd gear (limp mode), P0887 code present.
  ❌ Tried (didn't work) The user first suspected a software issue or wiring problem based on common knowledge.
  ✅ What actually fixed it The user load-tested the original battery and found it was weak. Replacing the original battery with a new one resolved the P0887 code and the limp mode issue. The theory is that the weak battery was causing voltage fluctuations that the sensitive TCM interpreted as a 'circuit high' fault.

OEM Part Supersession History

• N/A → 68467810AA — This is a known replacement part number for the Transmission Control Module (TCM) for the 2015-2022 model year range.
  Heads up: Replacement of the TCM requires dealer-level programming (Proxy Alignment) with wiTECH to integrate the module with the vehicle's network. It is not a plug-and-play part.

Model Year Variations Within This Range

• 2015-2016: These model years were subject to Safety Recall S24 for the corroded CAN-C bus connector under the driver's seat. They are also the primary focus of TSBs #21-018-17 REV. A/B/C and #21-039-15 REV A/B, which address P0887 with a software flash.
• 2017: The 2017 model is covered by TSB #2101717, which also specifies a software flash for P0887. While it was not part of the S24 recall for the under-seat connector, it shares the same fundamental 948TE transmission and software sensitivities as the earlier models.