NHTSA ID Number: 10152812
Manufacturer Communication Number: SIL 27-EP-18EN
TSB/Document Date: 2019-02-19
Summary
Announces the availability of the DC busbar and procedures for replacing the DC busbar located inside the DPIM2
SIL 27-EP-18
January, 2019
Page 1 of 38
SUBJECT:
Replacing the DC Busbar Inside the Dual Power Inverter Module 2 (DPIM2)
MODELS AFFECTED:
H 40/50 EPTM System Equipped With DPIM2
Tools Required
• J-51586 Tab Bending Tool
• Electrostatic Discharge Wrist Strap (Refer to Figure 2)
• Pick or Small Flat Blade Screwdriver
• Torx Plus® T8 Bit
• Torx Plus® T10 Bit
• Torx Plus® T20 Bit
• Torx Plus® T25 Bit
• Torx Plus® T25 6in Bit
• 4mm Hex Key
• 6mm Hex Key
• 8mm Hex Socket
• Loctite® 242
• Loctite® 425
Introduction:
This Service Information Letter (SIL) announces the availability of the DC Busbar (P/N 29546818) and includes
the procedure to replace the DC Busbar located inside the DPIM2. The availability of these parts eliminates the
need for a complete DPIM2 replacement under certain failure conditions.
NOTE: Components and replacement procedures are the same for Inverter A and Inverter B. Refer to
Figure 21 for GATE Drive Card locations.
Refer to Table 1 for related part numbers.
GJ / SL8213EN
4331354
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 2 of 38
Table 1. DPIM2 Busbar Parts Information
Part Name
DC Busbar
Part Number
Quantity
29546818
1
NOTE: Perform the necessary diagnosis prior to ordering the DC Busbar P/N 29546818. Contact Allison
TAC at (800) 252-5283 to confirm the DC Busbar failure.
Warranty Claim Information:
When a DC Busbar, P/N 29546818, is utilized to repair a failed DPIM2 under warranty, use DC Busbar part number
29546818 as the PFP and claim the part number in the Service Parts subsection of the AWAARE claim.
Diagnosis:
The DC Busbar may become damaged in various ways but typically it is due to high-voltage arcing when another
component in the DPIM2 fails. Examples include the passive discharge resistor burning which released conductive
particles into the DPIM2 housing. The conductive particles allow the DC+ and the DC- tabs connected to the
SKiM module to short and melt. Loose screws in the SKiM module or at the HVIL card can cause arc damage
(Refer to Figure 1)
Figure 1. Busbar Damage from Arcing
WARNING: DO NOT rely on the High Voltage Interlock Loop (HVIL) or control systems to de-energize
the system. Always perform the Electrical Disconnect Verification Procedure to be sure the system is
discharged before servicing components.
DO NOT attempt to bypass any High Voltage Interlock for any reason. Tampering with the HVIL may result
in injury. Failure to follow proper safety procedures may result in serious personal injury or death.
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 3 of 38
NOTE: Allison Transmission, Inc. requires that the DPIM be removed from the vehicle prior to component
replacement. Prior to removal of the DPIM, refer to the H 40/50 EPTM System Troubleshooting Manual
(TS5812EN) and perform the Electrical Disconnect Verification Procedure.
NOTE: The DC Busbar replacement should NOT be performed if excessive smoke and/or water damage
are present.
NOTE: Refer to the attachment at the end of this SIL for information regarding the name and location of
components within the DPIM2.
The procedures contained in this SIL are organized into the following sections:
Section 1: Removal of Main Cover and HVIL Circuit Card
Section 2: Removal of BCA Card Mounting Shelf
Section 3: Removal of the GATE Drive Cards
Section 4: DC Busbar Removal
Section 5: Installation of DC Busbar
Section 6: Installation of GATE Drive Cards
Section 7: Installation of BCA Card Mounting Shelf
Section 8: Installation of HVIL Circuit Card and Main Cover
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 4 of 38
Section 1: Removal of Main Cover and HVIL Circuit Card
NOTE: All circuit cards in the DPIM2 are sensitive to electrostatic discharge (ESD). ESD damage can be
caused by voltage levels that cannot be felt by humans. When working on the DPIM2, ALWAYS wear an
ESD wrist strap to ground any possible electrostatic charge. The strap should be worn around the wrist
with the alligator clip securely attached to the DPIM chassis. Refer to Figure 2.
Figure 2. Electrostatic Discharge Wrist Strap (Typical)
Plus®
1. Using a Torx
T25 bit, remove twenty-six (26) M5x18mm machine screws that secure the Main Cover
to the DPIM Housing (refer to Figure 3). Set the screws aside for reassembly. Remove the Main Cover.
Discard the cover gasket.
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 5 of 38
Figure 3. DPIM Main Cover
2. Exercising care, cut one (1) wire tie at location shown in Figure 4. Do NOT remove any wire ties that pass
through the HVIL Circuit Card. Leaving the severed wire ties in place will provide a visual aid for wire tie
locations during installation of the replacement circuit card.
Figure 4. HVIL Circuit Card – Wire Tie Location
3. Cut the two (2) wire ties at locations shown in Figure 5 and remove them from the mounts. The wire
tie mounts do NOT have to be removed from the DPIM Housing unless they interfere with the removal
or installation of the HVIL circuit card.
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 6 of 38
Figure 5. HVIL Circuit Card – Two (2) Wire Tie Locations
CAUTION: Do NOT pull on the wires when removing connectors; doing so may pull the pins out of the
connector.
4. When removing connectors, push down on the tab at Location 1 and push the harness out of the connector
at Location 2 (refer to Figure 6).
Figure 6. HVIL Circuit Card Connector Removal
5. Remove three (3) wire harness connectors from HVIL Circuit Card surface mount connectors by gently
depressing the retaining tab with a pick or small flat blade screwdriver. Refer to Figure 7.
NOTE: Use care to avoid bending or damaging the circuit card connectors.
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 7 of 38
Figure 7. HVIL Circuit Card – Three (3) Harness Connector Locations
WARNING: Any conductive material (i.e. screws, bolts, nuts, etc.) can cause a short inside the DPIM that
will result in permanent and irreversible DPIM damage. All hardware must be accounted for throughout
the service procedure.
6. Using an 8mm socket, remove the four (4) M5 nut/washer assemblies as shown in Figure 8. Disconnect the
two (2) wire ring terminals from the studs.
Figure 8. HVIL Circuit Card – Four (4) Mounting Nut/Washer Locations (M5)
7. Using a Torx Plus® T25 bit, remove the four (4) M5x30mm screws securing the HVIL Circuit Card as shown
in Figure 9.
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 8 of 38
Figure 9. HVIL Circuit Card – Four (4) Mounting Screw Locations (M5x30mm)
8. Using a Torx Plus® T25 bit, remove the two (2) M5x14mm screws securing the HVIL Circuit Card as shown in
Figure 10.
Figure 10. HVIL Circuit Card – Two (2) Mounting Screw Locations (M5x14mm)
9. Using a Torx Plus® T25 bit, remove the four (4) M5x22mm screws securing the HVIL Circuit Card as shown
in Figure 11.
Figure 11. HVIL Circuit Card – Four (4) Mounting Screw Locations (M5x22mm)
10. Lift the HVIL Circuit Card straight up and remove it from the DPIM Housing.
11. Verify that the choke is in place as shown in Figure 12.
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 9 of 38
NOTE: The choke may have adhered to the underside of the HVIL Circuit Card when it was removed. If
this has occurred, reinstall choke to its proper location as shown in Figure 12. The choke must be installed
with the arrow pointing toward the DC lug box.
(1)
–
Choke
Figure 12. Verification of Choke Installation
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 10 of 38
Section 2: Removal of BCA Card Mounting Shelf
1. Carefully cut and remove the wire ties retaining the wire harnesses (refer to Figure 13).
Figure 13. Wire Tie Locations
NOTE: Label the wires on connectors 2, 3, and 4 (refer to Figure 14) with the corresponding phase (A, B,
C) as indicated by the circuit card connector labels (CURR A, CURR B or CURR C) for reinstallation.
CAUTION: Failure to properly label the current sensor harnesses may lead to improper reinstallation
and cause the DPIM to not operate.
2. Remove five (5) wire harness connectors from circuit card surface mount connectors by gently depressing
the retaining tab with a pick or small flat blade screwdriver (refer to Figure 14 and Figure 15).
NOTE: Use care to avoid bending or damaging the circuit card connectors.
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 11 of 38
Figure 14. Wire Harness Connector Removal (4 Locations)
Figure 15. Wire Harness Connector Removal
3. Using a Torx Plus® T25 bit, remove the seven (7) M5x14mm screws securing the BCA Mounting Shelf
(refer to Figure 16).
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 12 of 38
Figure 16. BCA Mounting Shelf Fastener Locations
4. Carefully lift the BCA Mounting Shelf and set in on the side of the chassis as shown in Figure 17.
NOTE: Three (3) harnesses are still connecting the BCA Card to the GATE Drive Cards. Do NOT relocate
the BCA Mounting Shelf any farther than as shown in Figure 17.
Figure 17. BCA Mounting Shelf Relocation
5. Remove three (3) ribbon cable connectors from the GATE Drive Cards (refer to Figure 17) as follows:
a. Use the handle of Tab Bending Tool J-51586 to disengage and remove the cable strain relief cap
(refer to Figure 18).
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 13 of 38
Figure 18. Cable Strain Relief Cap Removal (BCA Cable Card Connector Shown for Clarity)
b. Press the tabs down on both sides of the GATE Drive Card Connector to release the ribbon cable
connector (refer to Figure 19).
Figure 19. Releasing the Ribbon Cable Connector (BCA Cable Card Connector Shown for Clarity)
6. Remove the BCA Mounting Shelf from the DPIM to gain access to the three (3) GATE Drive Cards.
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 14 of 38
Section 3: Removal of the GATE Drive Cards
CAUTION: The spring pins (refer to Figure 20) located in the SKiM module that contact the bottom of the
Gate Drive Card are NOT available for replacement if lost or damaged. Extreme caution must be used
during removal of any Gate Drive Cards to ensure no spring pins are damaged or lost.
Figure 20. SKiM Module Spring Pin
NOTE: Refer to Figure 21 for DPIM2 Phase Locations.
Figure 21. DPIM2 Phase Locations
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 15 of 38
1. Using a Torx Plus® T8 bit, remove the twelve (12) M3 x 8mm (coarse thread) screws from each of the six (6)
GATE Drive Cards (refer to Figure 22).
Figure 22. GATE Drive Card Fastener Locations (M3 x 8mm Coarse Thread – Quantity 12)
2. Using a Torx Plus® T10 bit, remove the four (4) M3 x 8mm (fine thread) screws and two (2) grounding
brackets from each of the six (6) GATE Drive Cards (refer to Figure 23).
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
SIL 27-EP-18
January, 2019
Page 16 of 38
Figure 23. GATE Drive Card Fastener Locations (M3 x 8mm Fine Thread) – Quantity 4
3. Carefully pry back the ten (10) white locking tabs (refer to Figure 24) to release each GATE Drive Card from
its mounting location and gently lift the cards straight up and away from the DPIM.
Copyright © 2019 Allison Transmission, Inc. All Rights Reserved.
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TSB/Document ID: SIL 27-EP-18EN
Replacement Service Bulletin Number:
MFR Communication Date: 2019-01-13
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: ELECTRICAL SYSTEM
MFR Component System:
MFR Component Subsystem:
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