MG
Moderator
Please see T-SB-0046-22
SUPERSESSION NOTICE:
The information contained in this bulletin supersedes Service Bulletin No. T-SB-0318-17.
The Repair Procedure section has been updated. Service Bulletin No. T-SB-0318-17 is obsolete and any printed versions should be discarded.
Introduction:
Some 2016-2019 model year Mirai vehicles may exhibit a warning message, "FC malfunction, return vehicle to dealer for service." This message is accompanied by Diagnostic Trouble Code (DTC) P1 DEF (450 FC Stack Performance). The Fuel Control Module (FCM) calibration has been revised to address this condition.
APPLICABLE WARRANTY:
This repair is covered under the Toyota Fuel Cell Vehicle System Component Warranty. This warranty is in effect for 96 months or 100,000 miles, whichever occurs first, from the vehicle's in-service date. Warranty application is limited to occurrence of the specified condition described in this bulletin.
Repair Procedure:
1. Using Techstream, check for the following stored OTC. P1 DEF - 450 FC Stack Performance. Is the OTC present?
YES- Continue to step 2.
NO - This bulletin does NOT apply. Continue diagnosis using the applicable Repair Manual.
2. Perform a stimulation test.
A. Connect Techstream to the DLC3.
B. Turn the power switch ON (READY).
C. Let the vehicle warm up for 5 minutes.
D. Turn Techstream ON.
(1) Enter the following menus: Powertrain - FC - Data List-All Data
E. Turn the vehicle OFF, then IG-ON.
F. Push the H20 button.
G. Confirm the H20 light is on.
H. Ready ON the vehicle.
I. Confirm the Ready light is ON, and then Ready OFF. The active drain water procedure
will begin.
J. The H20 light will turn OFF when the active drain water procedure is completed.
K. Drive the vehicle for 10 minutes.
L. Stop the vehicle in a safe location. M. Record a snapshot of the Data List.
Perform one of the following steps to achieve maximum power output and record the maximum values of FC Current, FC Voltage Before Boosting, and FC Stack Cell Minimum Voltage.
3. Check Techstream snapshot data - FC Current (maximum value). Is FC Current above 400A?
YES - Continue to step 4.
NO-The stimulation test MUST be performed until 400A or more is achieved.
5. Check Techstream snapshot data - FC Stack Cell Minimum Voltage Cell Channel No. Is the channel between 186ch and 195ch?
YES- Continue to step 6.
NO - Perform the stimulation test again.
6. Replace the fuel cell stack.
7. Check for the Authorized Modifications Label affixed to the vehicle in the location shown below. Confirm if the FCM calibration has been updated. Is the calibration ID listed the latest FCM calibration?
YES - This bulletin does NOT apply. Continue diagnosis using the applicable Repair Manual.
NO - Continue to step 8.
8. Flash reprogram the FCM
9. Prepare and install the Authorized Modifications Label
10. Start the engine and warm it up to normal operating temperature.
11. Test-drive the vehicle to confirm proper vehicle operation.
SUPERSESSION NOTICE:
The information contained in this bulletin supersedes Service Bulletin No. T-SB-0318-17.
The Repair Procedure section has been updated. Service Bulletin No. T-SB-0318-17 is obsolete and any printed versions should be discarded.
Introduction:
Some 2016-2019 model year Mirai vehicles may exhibit a warning message, "FC malfunction, return vehicle to dealer for service." This message is accompanied by Diagnostic Trouble Code (DTC) P1 DEF (450 FC Stack Performance). The Fuel Control Module (FCM) calibration has been revised to address this condition.
APPLICABLE WARRANTY:
This repair is covered under the Toyota Fuel Cell Vehicle System Component Warranty. This warranty is in effect for 96 months or 100,000 miles, whichever occurs first, from the vehicle's in-service date. Warranty application is limited to occurrence of the specified condition described in this bulletin.
Repair Procedure:
1. Using Techstream, check for the following stored OTC. P1 DEF - 450 FC Stack Performance. Is the OTC present?
YES- Continue to step 2.
NO - This bulletin does NOT apply. Continue diagnosis using the applicable Repair Manual.
2. Perform a stimulation test.
A. Connect Techstream to the DLC3.
B. Turn the power switch ON (READY).
C. Let the vehicle warm up for 5 minutes.
D. Turn Techstream ON.
(1) Enter the following menus: Powertrain - FC - Data List-All Data
E. Turn the vehicle OFF, then IG-ON.
F. Push the H20 button.
G. Confirm the H20 light is on.
H. Ready ON the vehicle.
I. Confirm the Ready light is ON, and then Ready OFF. The active drain water procedure
will begin.
J. The H20 light will turn OFF when the active drain water procedure is completed.
K. Drive the vehicle for 10 minutes.
L. Stop the vehicle in a safe location. M. Record a snapshot of the Data List.
Perform one of the following steps to achieve maximum power output and record the maximum values of FC Current, FC Voltage Before Boosting, and FC Stack Cell Minimum Voltage.
3. Check Techstream snapshot data - FC Current (maximum value). Is FC Current above 400A?
YES - Continue to step 4.
NO-The stimulation test MUST be performed until 400A or more is achieved.
5. Check Techstream snapshot data - FC Stack Cell Minimum Voltage Cell Channel No. Is the channel between 186ch and 195ch?
YES- Continue to step 6.
NO - Perform the stimulation test again.
6. Replace the fuel cell stack.
7. Check for the Authorized Modifications Label affixed to the vehicle in the location shown below. Confirm if the FCM calibration has been updated. Is the calibration ID listed the latest FCM calibration?
YES - This bulletin does NOT apply. Continue diagnosis using the applicable Repair Manual.
NO - Continue to step 8.
8. Flash reprogram the FCM
9. Prepare and install the Authorized Modifications Label
10. Start the engine and warm it up to normal operating temperature.
11. Test-drive the vehicle to confirm proper vehicle operation.