5­547

Allison H 40/50 EP

DTC 73–38 Inverter A Secondary Encoder Signal Lost (cont’d)
Step
13

Action
1.
2.
3.
4.

Value(s)

Turn OFF the ignition.
Disconnect the P1 encoder connector.
At J­50165­3, DPIM2 Overlay, measure for
shorts­to­ground on pins 6, 10, 8, and 22.
At J­50165­3, DPIM2 Overlay, measure for
shorts to other wires on pins 6, 10, 8, and
22.

Yes

No

Short in vehicle
harness. Repair
as necessary and
go to Step 20

Go to Step 14

Go to Step 15

Open or short in
vehicle harness.
Repair as
necessary and
go to Step 20

Go to Step 16

Open or short in
vehicle harness.
Repair as
necessary and
go to Step 20

NOTE: There will be continuity between pins
8 and 24 of the red/blue 32­way connector
because all motor speed sensor shield wires
are spliced together.
NOTE: The vehicle OEM has responsibility
for all external wiring harness repair. Harness
repairs performed by Allison Transmission
distributors and dealers are not covered by
Allison Transmission warranty.
Were any shorts­to­ground or shorts to any
other wires found?
14

1.
2.

3.
4.

Leave the ignition OFF.
Connect the J­50165, DPIM2 Adapter
Harness, to the red/blue DPIM 32­way
connector. Leave it connected to the
red/blue OEM 32­way connector and leave
the P1 encoder connector disconnected.
Turn ON the ignition.
Measure sensor supply voltage at the
P1 encoder connector on pin C.

DPIM1
10­13V
DPIM2
7.5­18V
(nominal ~12V)

NOTE: The vehicle OEM has responsibility
for all external wiring harness repair. Harness
repairs performed by Allison Transmission
distributors and dealers are not covered by
Allison Transmission warranty.
Is the voltage within the specified range?
15

5­548

1.
2.

Turn OFF the ignition.
Leave the P1 encoder connector
disconnected.
3. Use J­39197, Jumper Wire Kit, to measure
resistance to ground on pin B of the
P1 encoder connector.
Was the resistance within specification?

Less than 4
Ohms

Copyright © 2015 Allison Transmission, Inc. All Rights Reserved.

Section 5—DIAGNOSTIC CODES

DTC 73–38 Inverter A Secondary Encoder Signal Lost (cont’d)
Step
16

Action
1.
2.
3.
4.

5.

Leave the ignition OFF.
Leave the P1 encoder connector
disconnected.
Use J­39197, Jumper Wire Kit, to jumper
pins A and C on the P1 encoder connector.
Disconnect the red/blue DPIM 32­way
connector from J­50165, DPIM2 Adapter
Harness, leaving J­50165 mated to the
red/blue OEM 32­way connector.
At J­50165­3, DPIM2 Overlay, measure the
resistance between pins 10 and 6 of the
red/blue OEM 32­way connector.

Value(s)

Yes

No

Less than 4
Ohms

Go to Step 17

Open or short in
vehicle harness.
Repair as
necessary and
go to Step 20

Less than 4
Ohms

Go to Step 18

Open or short in
vehicle harness.
Repair as
necessary and
go to Step 20

NOTE: The vehicle OEM has responsibility
for all external wiring harness repair. Harness
repairs performed by Allison Transmission
distributors and dealers are not covered by
Allison Transmission warranty.
Was the resistance within specification?
17

1.
2.
3.
4.
5.

6.

Leave the ignition OFF.
Leave the P2 encoder connector
disconnected.
Remove the jumper wire from the
P2 encoder connector.
Use J­39197, Jumper Wire Kit, to jumper
pins A and B on the P2 encoder connector.
Leave the J­50165, DPIM2 Adapter
Harness, mated to the red/blue OEM 32­way
connector ONLY.
At J­50165­3, DPIM2 Overlay, measure the
resistance between pins 10 and 22 of the
red/blue OEM 32­way connector.

NOTE: The vehicle OEM has responsibility
for all external wiring harness repair. Harness
repairs performed by Allison Transmission
distributors and dealers are not covered by
Allison Transmission warranty.
Was the resistance within specification?
18

Replace the P1 speed sensor.
Has the speed sensor been replaced?

Go to Step 20

Replace the
speed sensor.
Go to Step 20

19

NOTE: In most cases, the Dual Power Inverter
Module (DPIM) is not at fault. Investigate
thoroughly before replacing the DPIM.

Go to Step 20

Replace DPIM.
Go to Step 20

Replace DPIM. Contact Technical Assistance
Center (TAC) at 1­800­252­5283 for
DPIM replacement authorization. TAC will
require a snapshot.
Is the replacement of the DPIM complete?

Copyright © 2015 Allison Transmission, Inc. All Rights Reserved.

5­549

Allison H 40/50 EP

DTC 73–38 Inverter A Secondary Encoder Signal Lost (cont’d)
Step
20

5­550

Action
To verify the repair:
1. Clear the DTC.
2. Operate the vehicle under normal driving
conditions.
Did the DTC return?

Value(s)

Yes

No

Begin the
diagnosis again.
Go to Step 1

System OK

Copyright © 2015 Allison Transmission, Inc. All Rights Reserved.

Section 5—DIAGNOSTIC CODES

DTC 73­39 (DPIM1) Inverter A Encoder Power Supply
Out­of­Range High

Figure 5–47.
Action Taken When DTC Sets:
• None
Possible Causes:
• Short to 12V or 24V power
Tool Requirements:
• Universal Allison DOC®
• J­39700 Universal Breakout Box
• J­46711 TCM/VCM/DPIM Breakout Harness
• J­46708 Multimeter
• J­39197 Jumper Wire Kit
Step

Action

1

Are any 13­XX series DTCs set along with this
code?

2

1. Install Universal Allison DOC®.
2. Start the engine.
3. Record the DTC snapshot.
4. Monitor TCM ignition voltage.
Is the voltage within the specified values?

3

Is DTC 73­39 active?

Value(s)

9–18V

Yes

No

Troubleshoot
these codes first.

Go to Step 2

Go to Step 3

Resolve voltage
problem. Go to
Step 20

Go to Step 5

Go to Step 4

Copyright © 2015 Allison Transmission, Inc. All Rights Reserved.

5­551

Allison H 40/50 EP

DTC 73­39 (DPIM1) Inverter A Encoder Power Supply
Out­of­Range High (cont’d)
Step

Action

4

1.
2.

5

Perform a visual inspection of the red 32­way
connector at the Dual Power Inverter Module
(DPIM), the P1 speed sensor, and the P2 speed
sensor.

Value(s)

Clear the DTC.
Attempt to duplicate the conditions in the
failure record (mode, temperature, etc.).
Does DTC 73­39 return?

Yes

No

Go to Step 5

System OK

Make repairs as
necessary and
go to Step 20

Go to Step 6

NOTE: The vehicle OEM has responsibility
for all external wiring harness repair. Harness
repairs performed by Allison Transmission
distributors and dealers are not covered by
Allison Transmission warranty.
Is there any water intrusion, damaged wiring,
etc. that may cause a loss and/or corruption of
signal?
6

Turn OFF the ignition.
Install J­39700, Universal Breakout
Box, to the DPIM 24­way and the
OEM 24­way connectors using J­46711,
TCM/VCM/DPIM Breakout Harness.
3. Turn ON the ignition.
Is the harness connected and the ignition turned
back ON?

7

At J­46711­1, DPIM Overlay, measure battery
supply voltage on pins 1, 2, 5, and 6 of the
DPIM 24­way connector.

1.
2.

Go to Step 7

10.5–16V

Go to Step 8

Open or short in
vehicle harness.
Repair as
necessary and
go to Step 20

9–16V

Go to Step 9

Open or short in
vehicle harness.
Repair as
necessary and
go to Step 20

NOTE: The vehicle OEM has responsibility
for all external wiring harness repair. Harness
repairs performed by Allison Transmission
distributors and dealers are not covered by
Allison Transmission warranty.
Is the voltage within the specified range?
8

At J­46711­1, DPIM Overlay, measure wakeup
signal voltage on pins 3 and 4 of the 24­way
connector.
NOTE: The vehicle OEM has responsibility
for all external wiring harness repair. Harness
repairs performed by Allison Transmission
distributors and dealers are not covered by
Allison Transmission warranty.
Is the voltage within the specified range?

5­552

Copyright © 2015 Allison Transmission, Inc. All Rights Reserved.

Section 5—DIAGNOSTIC CODES

DTC 73­39 (DPIM1) Inverter A Encoder Power Supply
Out­of­Range High (cont’d)
Step
9

Action
At J­46711­1, DPIM Overlay, measure torque
enable voltage on pins 16 (Inverter B Torque
Enable) and 17 (Inverter A Torque Enable) of
the 24­way connector.

Value(s)

Yes

No

9–16V

Go to Step 10

Open or short in
vehicle harness.
Repair as
necessary and
go to Step 20

Less than 4
Ohms

Go to Step 11

Open or short in
vehicle harness.
Repair as
necessary and
go to Step 20

NOTE: The vehicle OEM has responsibility
for all external wiring harness repair. Harness
repairs performed by Allison Transmission
distributors and dealers are not covered by
Allison Transmission warranty.
Is the voltage within the specified range?
10

1.
2.

3.

Turn OFF the ignition.
Disconnect the J­46711, TCM/VCM/
DPIM Breakout Harness, from the
DPIM 24­way connector. Leave the
OEM 24­way connector mated to the
J­46711.
At J­46711­1, DPIM Overlay, measure
resistance to ground on 12V battery return
pins 18, 19, 20, and 21 of the DPIM 24­way
connector.

NOTE: The vehicle OEM has responsibility
for all external wiring harness repair. Harness
repairs performed by Allison Transmission
distributors and dealers are not covered by
Allison Transmission warranty.
Was the resistance within specification?

Copyright © 2015 Allison Transmission, Inc. All Rights Reserved.

5­553

Allison H 40/50 EP

DTC 73­39 (DPIM1) Inverter A Encoder Power Supply
Out­of­Range High (cont’d)
Step

Action

Value(s)

Yes

No

11

Leave the ignition OFF.
Disconnect the DPIM 24­way and
OEM 24­way connectors from the J­46711,
TCM/VCM/DPIM Breakout Harness.
3. Connect the OEM 24­way connector to the
DPIM 24­way connector.
4. Disconnect the red OEM 32­way connector
from the DPIM.
5. Connect the red DPIM 32­way connector
of the J­46711, TCM/VCM/DPIM Breakout
Harness, to the DPIM connector ONLY.
Leave the J­46711 disconnected from the
red OEM 32­way connector.
6. Turn ON the ignition.
7. At J­46711­1, DPIM Overlay, measure the
speed sensor supply Open Circuit Voltage
(OCV) at the red 32­way connector by
measuring the voltage between pin 6 and
pin 22 of the red 32­way DPIM connector.
8. At J­46711­1, DPIM Overlay, measure the
speed sensor supply Open Circuit Voltage
(OCV) at the red 32­way connector by
measuring the voltage between pin 9 and
pin 25 of the red 32­way DPIM connector.
Were both voltages within the specified range?

10–13V

Go to Step 12

Go to Step 19

12

1.
2.

Short in vehicle
harness. Repair
as necessary and
go to Step 20

Go to Step 13

1.
2.

3.