2018-2020 Honda Clarity Plug-In Hybrid System Failure Message Comes On With DTC P1D8D

NHTSA ID Number: 10187007

Manufacturer Communication Number: A21-008

Summary

Service Bulletin – The Hybrid System Failure message comes on the MID, and DTC P1D8D (Generator Motor Inverter Short) is stored.

3 Affected Products

Vehicle


MAKE	MODEL	YEAR
HONDA	CLARITY PLUG-IN HYBRID	2018-2020

SYMPTOM

The Hybrid System Failure message comes on the MID, and DTC P1D8D (Generator Motor Inverter Short) is stored.

POSSIBLE CAUSE

There is an internal failure of the Powertrain Control Unit (PCU).

CORRECTIVE ACTION

Replace the PCU.

PARTS INFORMATION

Part Name	Quantity	Part Number
Power Control Unit Assembly (PCU)	1	1B000-5WJ-A05
Cable Connector Bolt	1	90130-5WM-A01
DT Drain Plug O-Ring	1	19012-671-300

REQUIRED MATERIALS

Part Name

Quantity

Part Number

Coolant Type 2

OL999-9011

REPAIR PROCEDURE

WARNING

The power cables carry high voltage when the electric power system is energized. To avoid serious injury from electrical shock, do not turn on the system with the power cables disconnected.
Wear insulated gloves and use insulated tools to protect you from electrical shock. When removing or installing high voltage items, always use them. Wrap the high voltage items with protective tape after removing. Please be careful when you see on the illustration.

1. Turn the vehicle to ON.

2. Connect the i-HDS.

3. Select ELECTRIC POWERTRAIN system.

4. Check and clear DTC P1D8D, and note if any other DTCs are stored.

5. Turn the vehicle to OFF.

6. Make sure the charging connector is not connected to the vehicle.

7. Disconnect and isolate the negative cable with the 12-volt battery sensor from the 12-volt battery.

NOTE:

Always disconnect the negative side first.
To protect the connector from damage, do not hold it when removing the terminal.
Do not disconnect the 12-volt battery sensor from the negative cable.

8. Open the cover. Remove it if necessary.

9. Disconnect the positive terminal from the 12-volt battery.

10. Remove the bolt between the rear seat-back and the rear seat cushion.

11. While pushing down on the seat cushion, pull the seat hook handles to release the hooks.

12. Remove the rear seat cushion.

13. Remove the service plug hole cap.

14. Remove the Intelligent Power Unit (IPU) service plug hole lid.

15. Raise the lever for service plug B while pushing and sliding the tab in the direction of the arrow.

16. Remove service plug B.

17. Raise the lever for service plug A while pushing and sliding the tab in the direction of the arrow.

18. Remove service plug A.

19. Wrap the service plug base with protective tape.

20. Connect the positive terminal to the 12-volt battery.

NOTE: Always connect the positive side first.

21. Connect the negative cable and the 12-volt battery sensor to the 12-volt battery.

NOTE: To protect the connector from damage, do not hold it when installing the terminal.

22. Turn the vehicle to ON.

23. Select ELECTRIC POWERTRAIN system.

24. Select DATA LIST and check that V1 VOLTAGE (W1INV) is 30V or less.

NOTE: If V1 VOLTAGE (W1INV) is higher than 30V, wait until it becomes 30V or less.

25. Make sure the DT coolant is cool, then carefully remove the DT coolant expansion tank cap.

26. Remove the clips and hardware securing the front under cover.

2020 models only: Unclip the acoustic vehicle alerting speaker.

27. Loosen the DT coolant drain plug and drain the coolant.

28. After the coolant has drained, tighten the DT drain plug with a new O-ring.

29. Disconnect the PCU connector and the noise filter.

30. Disconnect the PCU coolant inlet and outlet hoses.

31. Remove the power cable clamps. Loosen the power cable connector bolt, then disconnect the power cable connector.

NOTE: If you see any damage, scratches, or deterioration of the coating on the aluminum portion of the connector or plastic parts, replace the cable.

32. Wrap the connector with protective tape.

33. Apply protective tape to the connector as shown.

34. Using pliers, move the bolt clip in the direction shown.

35. Position 2 pairs of long nose pliers on the areas as shown and remove the bolt clip by gripping the pliers tightly.

Then, replace the bolt.

36. Place the bolt clip as shown. Position a pair of pliers on the areas as shown and install the clip by gripping the pliers tightly.

NOTE: Install the bolt clip into the bolt groove, not into the threads.

37. Remove the PCU mounting bolts.

38. Loosen the three phase bolt and remove the PCU.

39. Remove the PCU coolant outlet hose and brackets, then install them on the new PCU.

40. Install the new PCU assembly and removed parts in the reverse order of removal.

NOTE:

Tighten the three phase bolt first, then tighten the PCU mounting bolts.
Torque all fasteners to specification.

41. Attach a clear rubber hose to the breather bolt.

42. Loosen the breather bolt.

43. Install a coolant fill funnel to the DT expansion tank.

44. Pour Honda Long Life Antifreeze/Coolant Type 2 until the coolant fill funnel is filled.

NOTE: Pour coolant into the fill funnel as necessary during the bleeding process.

45. Wait until the bubbles stop coming out from the clear rubber hose, then tighten the breather bolt.

46. Connect a fully charged jumper battery to the vehicle, and leave it connected during the entire procedure to maintain steady voltage.

47. Turn vehicle to ON.

48. On the i-HDS, select the ELECTRIC POWERTRAIN system, then ADJUSTMENT, then DT COOLANT AIR BLEEDING. Select START to start the air bleeding.

NOTE:

Do not run the DT electric water pump without coolant in the cooling system.
Do not loosen the breather bolt when running the DT electric water pump.
Watch the electric water pump speed during the procedure. If you do not see the speed fluctuate or hear operating noise from the water pump, exit the function and start over. In some cases, it may be necessary to restart the i-HDS.

49. Run the air bleeding for 10 minutes, then select STOP.

50. Exit the air bleeding and turn vehicle to OFF. Loosen the breather bolt and wait until the bubbles stop coming out of the clear rubber hose.

51. Tighten the breather bolt.

52. Remove the coolant fill funnel and the clear rubber hose.

53. Check the coolant level in the DT coolant expansion tank.

54. Turn the vehicle to ON.

55. On the i-HDS, select ADJUSTMENT MENU in the ELECTRIC POWERTRAIN system. Select MOTOR ROTOR POSITION SENSOR LEARNING, and follow the screen prompts.

56. Turn the vehicle to OFF.

57. Disconnect the 12-volt battery as shown in steps 7 through 9.

58. Install IPU service plugs A and B.

59. Do an all-DTC check and make sure DTC P1D8D is no longer present. If P1D8D is still stored, continue with normal troubleshooting.

NOTE: Some DTCs may have been introduced when V1 VOLTAGE (W1INV) was checked.

60. Install the remaining removed parts in the reverse order of removal.

NOTE: Torque all fasteners to specification.

1 Associated Document

Manufacturer Communications

A21-008
February 11, 2021
Version 1

https://www.nhtsa.gov/recalls?nhtsaId=10187007

MC-10187007-0001.pdf 2683.82KB

⬇ Download PDF (2.56 MB)

SaleBestseller No. 1

FOXWELL Car Scanner NT604 Elite OBD2 Scanner ABS SRS Transmission, Check Engine Code Reader for Cars and Trucks, Diagnostic Scan Tool with SRS Airbag, Automotive Diagnostic Tool with Live Data

[Easy to Use—Work Out of the Box] + [FOXWELL 2026 New Version] FOXWELL NT604 Elite scan tool is the 2026 new version from FOXWELL, designed for car owners who want to figure out the cause of issues before fixing car problems by scanning common systems like ABS, SRS, engine, and transmission. The NT604 Elite obd2 scanner diagnostic tool comes with the latest software—no need to waste time downloading software first. Plug the scanner into the OBDII port with OBDII cable to start the diagnosis.
[Affordable] + [Reliable Car Health Monitor] Will you be confused what happens when the warning light of ABS/SRS/transmission/check engine flashes? Instead of taking your cars to dealership, this FOXWELL scanner will help you do a thorough scanning and detection for your cars and pinpoint the root cause. Note：The device is a diagnostic tool, not a repair tool. To turn off a warning light, you must first physically repair the issue causing it. Only then can the scanner be used to clear the corresponding fault code.
[5 in 1 Car Diagnostic Scanner] Compared with obd scanners (50-100), NT604 Elite code scanner not only includes their OBDII diagnosis but also serves as ABS/SRS scanner, transmission and check engine code reader. When it’s an odb2 scanner, you can use it to check if your car is ready for annual test through I/M readiness menu. In addition, live data stream, built-in DTC library, data play back and print, all these features are a big plus for it. Note: doesn't support maintenance functions like reset or relearn. For the SRS system, NT604 Elite can read and clear common fault codes not caused by a crash, but crash/collision data cannot be cleared.
[Fantastic AUTOVIN] + [No extra software fee] Through the AUTOVIN menu, this NT604 Elite car scanner allows you to get your V-IN and vehicle info rapidly, no need to take time to find your V-IN and input one by one. What's more, the NT604 Elite ABS SRS scanner supports 60+ car brands from worldwide (America/Asia/Europe). You don’t need to pay extra software fee. AUTOVIN may not work on some older vehicles or certain vehicle brands. If AUTOVIN fails, please input the vin code manually or go to the Diagnostic Menu to select your vehicle model.
[Solid protective case KO plastic carrying bag] + [Lifetime update] Almost all same price-level car scanner diagnostic tool only offers plastic bag to hold the scanner.However, NT604 Elite automotive scanner is equipped with solid protective case, preventing your obd2 scanner from damage. Then you don’t need to pay extra money to buy a solid toolbox.

SaleBestseller No. 2

ANCEL AD310 Classic Enhanced Universal OBD II Scanner Car Engine Fault Code Reader CAN Diagnostic Scan Tool, Read and Clear Error Codes for 1996 or Newer OBD2 Protocol Vehicle (Black)

CEL Doctor: The ANCEL AD310 is one of the best-selling OBD II scanners on the market and is recommended by Scotty Kilmer, a YouTuber and auto mechanic. It can easily determine the cause of the check engine light coming on. After repairing the vehicle's problems, it can quickly read and clear diagnostic trouble codes of emission system, read live data & hard memory data, view freeze frame, I/M monitor readiness and collect vehicle information.
Sturdy and Compact: Equipped with a 2.5 foot cable made of very thick, flexible insulation. It is important to have a sturdy scanner as it can easily fall to the ground when working in a car. The AD310 OBD2 scanner is a well-constructed mechanic tool with a sleek design. It weighs 12 ounces and measures 8.9 x 6.9 x 1.4 inches. Thanks to its compact design and light weight, transporting the device is not a problem. The buttons are clearly labelled and the screen is large and displays results clearly.
Accurate Fast and Easy to Use: The AD310 scanner can help you or your mechanic understand if your car is in good condition, provides exceptionally accurate and fast results, reads and clears engine trouble emission codes in seconds after you fixed the problem. This device will let you know immediately and fix the problem right away without any car knowledge. No need for batteries or a charger, get power directly from the OBDII Data Link Connector in your vehicle.
OBDII Protocols and Car Compatibility: Many cheap scan tools do not really support all OBD2 protocols. AD310 scanner as it can support all OBDII protocols such as KWP2000, J1850 VPW, ISO9141, J1850 PWM and CAN. This device also has extensive vehicle compatibility with 1996 US-based, 2000 EU-based and Asian cars, light trucks, SUVs, as well as newer OBD2 and CAN vehicles both domestic and foreign. Pls confirm with our customer service whether it is compatible with your vehicle before purchasing.
Home Necessity and Worthy to Own: This is an excellent code reader to travel or home with as it weighs less and it is compact in design. You can easily slide it in your backpack as you head to the garage, or put it on the dashboard, this will be a great fit for you. The AD310 is not only portable, but also accurate and fast in performance. Moreover, it covers various car brands and is suitable for people who just need a code reader to check their car.

SaleBestseller No. 3

THINKCAR THINKSCAN 689 OBD2 Scanner, Bidirectional Scan Tool with 34+ Reset, 3000+ Active Test, ECU Coding, PMI, Wired Full System Diagnostic Scanner for Cars, CANFD/DOIP, FCA SGW AutoAuth

【Warm Tips】Wired THINKSCAN 689 is connected through a detachable OBDII cable, and we also have added OBD2 Extension Cable (about 60 cm/2 feet) as g ift, enabling customers handling vehicle repairs with ease. Just click "Bundles Item" above to get it. Note: FCA AutoAuth is a third-party service, additional cost may be required.
【Professional Car Diagnostic Tool】Tired of renew fees? Thinkscan 689 scanner provides dealer-level advanced functions without annual fees for auto mechanics and repair shops. 34+ Services, 3000+ Active Test, ECU Coding, 140+ Brands Coverage, FCA AutoAuth, CANFD&DOIP Protocol, Component Matching, Power Balance, V.A.G Guided, Compatible with Google Chrome integration, etc. With strong hardware backing, 64G Memory, Android 10, 4-core processors, and 4150mAh battery. Thinkscan 689 brings you the best as your daily business helper and never lets you drop the ball!
【Over 34 Reset Service, Adaptation + Relearn + Calibration + Initialization + Matching】Made for workshops, Thinkscan 689 scanner provides 34+ services for worldwide vehicles: such as Gear/SAS/EPB/TPMS/D.P.F/I.M.M.O/BMS/ETS/Oil/Brake/AFS/GEARBOX/SUNROOF/SUS Reset, ABS Bleed, Injector coding, etc. Warm tips: Compatibility may vary on vehicles' model and year, please contact seller before purchase to make sure it works well on your cars.
【Real Active Test】Thinkscan 689 scan tool features over 3000+ full bi-directional control ability, to send commands to vehicle’s systems/components, to verify system input/output without using the vehicle's controls, e.g. turn on the radiator fan, modulate the throttle, open/close windows, operate mirrors, Injector Buz Test, turn on interior&exterior lights, sound horn, test door lock actuators, turn on/off front/rear side ACM Solenoid, Vehicle level position calibration, Wheel Speed Sensor Supply.
【Comprehensive Solutions with Advanced Features】Take your vehicle customization to the next level with the Thinkscan 689's advanced ECU coding capabilities. This scan tool provides power balance, PMI, unlock more new features and enhance performance by activating dormant functions, customizing OE settings, matching replaced components, and reprogramming adaptive data to elevate your driving experience. Note: Compatibility varies by car models, please check before order.

SaleBestseller No. 4

BLCKTEC 460T OBD2 Scanner Car Code Reader Engine ABS SRS Transmission Diagnostic Tool, 12 Reset Services, Oil/TPMS/EPB/BMS/SAS/DPF/Throttle Reset, ABS Bleeding, Battery Test, Auto VIN, Free Update

[All System Diagnostics, Professional-Level Scanner] - BLCKTEC 460T is the ultimate OBD2 diagnostic tool for home mechanics and professionals. It supports all 10 OBD2 modes, reads and clears Engine/Transmission/ABS/SRS codes, performs All-System Diagnostics, offers workshop reset tools, and provides real-time live data. It helps you pinpoint issues, assess your car's condition, and prepare for SMOG checks with ease. NOTE: Function availability depends on your vehicle. Before you buy, be sure to use the Compatibility Checker on BLCKTEC website or contact our customer support to verify that the features you need are supported for your vehicle’s specific year, make, and model.
[12+ Most Popular Reset Functions] - BLCKTEC 460T OBD2 scanner offers 12+ dealer-level service functions, including Oil Maintenance Reset, ABS Bleeding, EPB Reset, SAS(Steering Angle Sensor) Recalibration, DPF(Diesel Particulate Filter) Reset, Throttle Body Relearn, Battery Reset/Initialization, TPMS Relearn, Transmission Reset, Fluid Change Reset, Maintenance Reset and more, enabling you to perform workshop services like a pro. NOTE: Function availability depends on your vehicle. Be sure to use the Compatibility Checker on BLCKTEC website to verify that the features you need are supported for your vehicle.
[Real-Time OBD2 and OEM Live Data, Freeze Frame Data] - BLCKTEC 460T helps diagnose vehicle issues when warning lights like Check Engine Light or ABS/SRS Light appear. It offers detailed DTC info, ECU Freeze Frame Data, and real-time OBD2 and advanced OEM live data, including Engine, Transmission, ABS, SRS, and more, making it easy to diagnose and resolve vehicle problems. You can view, graph, record, replay, and overlay up to four live data streams in a single graph for better analysis.
[AutoVIN, AutoReLink, AutoScan, 3X Faster] - Equipped with AutoVIN technology, 460T automatically retrieves the VIN to save you time. Its AutoScan and AutoReLink features scan all of the vehicle's ECUs and detect any fault codes immediately after you plug the scanner into the vehicle's OBD2 port - no button presses required. Additionally, it regathers DTC and I/M readiness information every 30 seconds, simplifying monitor tests. 460T's advanced technology makes it 3X faster than other products.
[Get RepairSolutions2, the #1 Auto Repair App for Free] - When paired with RepairSolutions2(RS2) App, 460T becomes even more powerful. RS2's Verified Fix Database built by master technicians, provides the parts needed for the repair. Additionally, RS2 gives you access to OEM warranty info, maintenance schedules, TSB, and dealership recall info, making car care easier than ever. RS2 is free with no subscription fees and it stores your car scan reports in the cloud, allowing you to access, share, or print them anytime and anywhere.

SaleBestseller No. 5

BlueDriver Pro Next Gen OBD2 Scanner – No Subscription, Bluetooth Car Code Reader for iPhone & Android – Diagnose 8000+ Issues, ABS SRS TPMS, Repair Reports, Vehicles 1996+

[Diagnose Like a Pro] BlueDriver Pro Next-Gen is a professional OBD2 scanner and diagnostic tool that helps you scan, understand, and clear vehicle trouble codes with confidence. Turn your phone into a powerful car diagnostic scanner—no guesswork, no unnecessary repairs.
[Read and Clear More Codes Than Ever] Read and clear more codes than basic car code readers. Access enhanced diagnostics for Check Engine, ABS, SRS, Airbag, TPMS, Transmission, and more on supported vehicles, including expanded coverage on newer model years.
[Verified Fixes and Real-Time Data] Get unlimited, technician-verified repair reports matched to your VIN, with definitions, causes, and confirmed fixes. Monitor live vehicle data as you drive, view freeze frames, check smog readiness, and analyze Mode 6 test results.
[Expanded Make & Model Coverage] Optimized for today’s vehicles with strong support for GM, Ford, Stellantis (RAM, Jeep, Chrysler), Toyota, Honda, Nissan, Mazda, Subaru, Hyundai, Mercedes-Benz, BMW, and VW. Enhanced communication on select 2024+ Nissan and Mazda models (see compatibility chart).
[Gas Vehicles 1996+ & Select Light-Duty Trucks] Works with all gas-powered vehicles made in 1996 or newer, plus select light-duty trucks and diesels, including F-250, RAM 2500, Silverado, and Sierra. Built for daily drivers, family vehicles, and real-world truck use.