P2610 on 2014-2015 Lexus IS 250: Engine Off Timer Performance Causes and Fixes

What's Unique About the 2014-2015 Lexus IS 250

For this specific generation of IS 250, the P2610 code is a well-documented issue that Lexus acknowledged as a software logic problem. The manufacturer issued Technical Service Bulletin L-SB-0036-16 with a direct fix. The TSB states the ECM logic was modified to 'reduce the possibility of this condition.' Unlike in other vehicles where this code might lead to a complex diagnosis of wiring or component failure, the cause on the 2014-2015 IS 250 is almost certainly the ECM software needing an update, making the diagnosis very straightforward.

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 is on
• Inability to pass an emissions inspection

Most Likely Causes

1. Engine Control Module (ECM) Software Requires Update 🔴 High Probability → Shop Engine Control Module (ECM) Lexus officially identified this as a software issue and released Technical Service Bulletin L-SB-0036-16 to correct the ECM logic for 2014-2015 IS 250 models. The original logic was overly sensitive. 🎬 See a breakdown of what the P2610 timer code means.
   How to confirm: A Lexus dealer or a qualified shop with Toyota/Lexus Techstream software can check the vehicle's current calibration ID and compare it to the new ID specified in the TSB. The TSB applies to specific calibration IDs that are known to be faulty.
   Typical fix: Flash reprogram the ECM with the updated software calibration file provided by Lexus. The TSB explicitly states the ECM should NOT be replaced for this condition. The repair is covered under the Lexus Federal Emission Warranty (96 months or 80,000 miles).
   Est. part cost: $0
2. Weak or Failing 12V Battery ⚪ Low Probability → Shop Vehicle Battery Low system voltage during startup or shutdown can cause various electronic glitches in control modules, including timer performance codes. This can happen on any modern, computer-controlled vehicle.
   How to confirm: Test the 12V battery with a digital multimeter or a professional electronic battery tester with a load test function. A healthy battery should read approximately 12.6 volts with the engine off and above 13.5 volts when the engine is running. A forum member on ClubLexus with a 2015 IS 250 reported that replacing a bad battery resolved their P2610 code.
   Typical fix: Replace the 12V battery.
   Est. part cost: $150-$300

Rare But Worth Checking

• Faulty Engine Control Module (ECM): → Shop Engine Control Module (ECM) This is extremely rare. The official TSB warns against replacing the ECM for this code. This should only be considered as a last resort after the software update has been performed and the battery is confirmed to be in excellent health.

Diagnosis Steps

1. Use an OBD-II scanner to confirm that P2610 is the only code present. If other codes are stored, diagnose them first.
2. Check the health of the 12V battery. Ensure it is fully charged and passes a load test. A simple voltage check is not always sufficient. Verify that the battery terminals are clean and tight.
3. Contact a Lexus dealership with your Vehicle Identification Number (VIN). Ask the service department if TSB L-SB-0036-16 is applicable to your vehicle and if the software update has already been performed by checking the vehicle's service history.
4. If the TSB applies and has not been completed, schedule an appointment to have the ECM reprogrammed. This is the most likely solution and should be covered under the 96-month/80,000-mile Federal Emissions Warranty.
5. If the TSB has already been performed or does not apply, and the battery is in perfect health, proceed with more advanced diagnostics, such as checking the ECM's power (+B) and ground (E1) circuits for integrity and looking for any signs of electrical interference.

Parts You'll Likely Need

• 12V AGM Battery (OEM #28800-38100) — While the primary cause is software, a weak battery can cause a wide range of electrical issues, including this timer performance code. It should be ruled out early. The OEM battery is a Group 24 size. 🎬 Watch: Step-by-step guide to replacing your Lexus 12V battery.
  Trusted brands: Lexus/Toyota Genuine, Interstate, DieHard, ACDelco, Optima
  OEM price range: $250-$400
  Aftermarket price range: $200-$330

Technical Service Bulletins (TSBs) & Recalls

• L-SB-0036-16: Dated July 11, 2016, this TSB specifically addresses DTC P2610 on 2014-2015 IS 250 models. It confirms the cause is overly sensitive ECM logic and the fix is a software reprogram. The repair is covered under the Lexus Federal Emission Warranty (96 months or 80,000 miles).
• L-SB-0002-18: This is a broader TSB from Jan 23, 2018, that also addresses P2610 for many other 2014-2017 Lexus models, including the IS 350, GS 350, and RC 350, indicating the timer logic issue was present across multiple platforms.

Platform-Specific Known Issues

• Per Lexus Technical Service Bulletin L-SB-0036-16, some 2014–2015 IS 250 vehicles may exhibit a MIL 'ON' condition with DTC P2610 due to the Engine Control Module (ECM) logic. The bulletin provides a software update to fix the condition and explicitly warns not to replace the ECM.
• The repair is covered under the Lexus Federal Emission Warranty, which is in effect for 96 months or 80,000 miles, whichever occurs first, from the vehicle's in-service date.

Mechanic-Grade Diagnostic Values

• ECM Reprogramming Voltage — expected: Stable 13.5 Volts. Failure: Voltage fluctuation or dropping below 13.5V during the reflash can corrupt the ECM.
• ECM Constant Power Supply (+B pin) — expected: Approximately 12.6 Volts (Battery Voltage) with ignition off. Failure: No voltage or significantly lower voltage indicates a wiring or fuse issue between the battery and ECM.
• ECM Ignition Power Supply (IGSW pin) — expected: Approximately 12 Volts when ignition switch is ON. Failure: No voltage when the key is on points to a problem with the ignition switch or associated relay/fuse.

Scan Tool Commands That Help

• Toyota Techstream: Live Data List -> 'Engine Off Timer' — To monitor the timer's behavior in real-time during advanced diagnosis to see if it is functioning correctly, especially if the TSB has already been performed.
• Toyota Techstream: Utility -> All Readiness -> Input DTC P2610 — To check the status of the P2610 monitor and confirm if the system is malfunctioning after a drive cycle, which is more specific than just checking for active codes.
• Toyota Techstream: ECU Flash Reprogramming — This is the primary function used to perform the software update as specified in TSB L-SB-0036-16.

Wiring & Ground Locations

• E1 — Likely located on the left rear of the engine compartment.. This is a primary ground point for the engine control system. A poor connection here can cause a host of electrical issues for the ECM, potentially including timer performance faults. This location is based on wiring diagrams for the same engine in a slightly older model.
• +B Pin at ECM — At the Engine Control Module connector.. This pin provides constant battery power to the ECM to maintain its memory, including the internal clock's status when the vehicle is off. An intermittent connection or voltage drop here can corrupt the timer.
• IGSW Pin at ECM — At the Engine Control Module connector.. This pin receives power when the ignition switch is turned on. Instability in this signal could confuse the ECM about the engine's run/stop state, contributing to the timer fault.

Real Owner Repair Stories

• ClubLexus user 'robd88' (2015 Lexus (model not specified but in IS forum context)) — Check Engine Light with code P2610.
  ❌ Tried (didn't work) Initial diagnosis was unclear.
  ✅ What actually fixed it The 12V battery tested bad. After installing a new battery and clearing the code, the issue was resolved, confirming that low battery voltage was the root cause.

OEM Part Supersession History

• 89661-53N70, 89661-53N71 → 89661-53N72 — Updated software logic to address DTC P2610.
• 89661-53N80, 89661-53N81 → 89661-53N82 — Updated software logic to address DTC P2610.
• 89661-53R30 → 89661-53R31 — Updated software logic to address DTC P2610.
• 89661-53R40 → 89661-53R41 — Updated software logic to address DTC P2610.

Model Year Variations Within This Range

• 2014 vs 2015: The Engine Control Modules (ECM) have different base part numbers and updated calibration files between the 2014 and 2015 model years, as well as between 2WD and 4WD models. It is critical to use the correct software update for the specific vehicle configuration as detailed in TSB L-SB-0036-16.