Revisions to this document are noted
by a stripe in the left­hand margin

SUBJECT:

#1707, Rev. C
August, 2013
Page 1 of 12

Troubleshooting Techniques for Low Power Complaints with Cummins ISB/ISL Engine

MODELS AFFECTED:

Allison H 40/50 EP SystemTM

Introduction:
The purpose of this bulletin is to provide the Servicing Technician with additional information and troubleshooting
techniques in diagnosing engine low power complaints in conjunction with Diagnostic Trouble Codes (DTCs) in
the Main Code 17 & 65 category. Table 1 contains the Diagnostic Trouble Codes most often associated with a
low power complaint in the H 40/50 EP SystemTM.
Table 1. Diagnostic Trouble Codes Associated With Engine Performance
Description

DTC

Failure Record

PBSS Display

Lamp

17­22

Engine Speed Profile
Mismatch

No

Yes

65­12

Engine Controller Stop

Yes

No

Stop Engine Lamp

65­13

Engine Controller
Warning

No

No

Check Engine Lamp

65­14

Engine Controller
Malfunction Indicator
Lamp

No

No

65­15

Engine Controller Protect

Yes

No

Flash Stop Engine Light

65­16

Engine Protection
System Shutdown

Yes

Yes

Stop System (Stop Engine
Lamp) Disable Propulsion

65­17

Engine Controller Idle
Shutdown

No

Yes

Flash Stop System

65­23

Engine Torque
Verification

Yes

Yes

Stop System

65­24

Engine Torque
Verification at Neutral

Yes

Yes

Check System

65­25

Engine Failed to Crank

No

No

65­26

Engine Performance

Yes

Yes

WBD / SL5581EN

69323

Copyright © 2013 Allison Transmission, Inc. All Rights Reserved.

#1707, Rev. C
August, 2013
Page 2 of 12

Diagnostic Trouble Code (DTC) Descriptions:
DTC 17­22

Engine Speed Profile Mismatch

Description: This DTC will be logged when a deviation (greater than 200 rpm) is detected between the Requested
Engine Speed and Actual Engine Speed.
Service: Retrieve the engine Fault Code(s) and refer to the Fault Code troubleshooting tree(s) in the appropriate
Cummins Troubleshooting and Repair manual.
NOTE: The H 40/50 EP SystemTM over­speed faults (codes with a main code of 81) may be logged
in conjunction with this code.
DTC 65­12

Engine Controller Stop

Description: This DTC is logged when the engine has or will shutdown. The engine sends an Engine Controller
Stop message to the hybrid system indicating that it has detected a fault associated with the engine and will
illuminate the stop engine lamp. Typically, the engine will shutdown to protect hardware from extreme conditions,
i.e. engine overheat or low oil pressure.
Service: The Engine Control Module (ECM) will have stored a Fault Code associated with this condition. Retrieve
the engine Fault Code(s) and refer to the Fault Code troubleshooting tree(s) in the appropriate Cummins
Troubleshooting and Repair manual.
NOTE: The H 40/50 EP SystemTM does not shutdown the engine or illuminate any dash lamps during
this diagnostic condition.
DTC 65­13

Engine Controller Warning

Description: This DTC is logged when the engine sends an Engine Controller Warning message to the hybrid
system indicating that it has detected a fault associated with the engine and will illuminate the check engine lamp.
Service: The engine ECM will have stored a Fault Code associated with this condition. Retrieve the engine
Fault Code(s) and refer to the Fault Code troubleshooting tree(s) in the appropriate Cummins Troubleshooting
and Repair manual.
NOTE: The H 40/50 EP SystemTM does not shutdown the engine or illuminate any dash lamps during
this diagnostic condition.
DTC 65­14

Engine Controller Malfunction Indicator Lamp

Description: This DTC is logged when the engine sends a message to the hybrid system indicating that it has
detected a fault associated with the engine and will illuminate the Malfunction Indicator Lamp (MIL).
Service: Typically, the MIL is illuminated when a diagnostic condition exists associated with the emission control
system of the engine. The engine ECM will have stored a Fault Code associated with this condition. Retrieve
the engine Fault Code(s) and refer to the Fault Code troubleshooting tree(s) in the appropriate Cummins
Troubleshooting and Repair manual.

Copyright © 2013 Allison Transmission, Inc. All Rights Reserved.

#1707, Rev. C
August, 2013
Page 3 of 12

NOTE: The H 40/50 EP SystemTM does not shutdown the engine or illuminate any dash lamps during
this diagnostic condition.
DTC 65­15

Engine Controller Protect

Description: This DTC is logged when the engine sends an Engine Controller Protect message to the hybrid system
indicating that it has detected a fault associated with the engine that may warrant an engine shutdown condition.
Service: The engine ECM will have stored a Fault Code associated with this condition. Retrieve the engine
Fault Code(s) and refer to the Fault Code troubleshooting tree(s) in the appropriate Cummins Troubleshooting
and Repair manual.
NOTE: The H 40/50 EP SystemTM does not shutdown the engine or illuminate any dash lamps during
this diagnostic condition.
DTC 65­16

Engine Protection System Shutdown

Description: This DTC is logged when the engine has detected a condition that warrants an engine shutdown (i.e.
engine overheat or low engine oil pressure).
Service: The engine ECM will have stored a Fault Code associated with this condition. Retrieve the engine
Fault Code(s) and refer to the Fault Code troubleshooting tree(s) in the appropriate Cummins Troubleshooting
and Repair manual.
DTC 65­17

Engine Controller Idle Shutdown

Description: Engine controller idle shutdown is an adjustable engine parameter setting. The setting is customer
programmable and designed to shutdown the engine while in neutral at idle after a specified period of time.
Service: Engine controller idle shutdown must be disabled with the H 40/50 EP SystemTM (see Customer
Adjustable Engine Parameter Settings). The Customer Adjustable Engine Parameters can be verified using the
Cummins INSITE tool.
DTC 65­23

Engine Torque Verification

Description: This DTC is logged when there is a large deviation (greater than 500 N∙m) between reported and
estimated engine torque while in Forward or Reverse. Either the engine is not producing enough torque or the
engine is producing too much torque.
Service: There may not be an ECM code associated with this condition. Refer to the Engine Performance
Troubleshooting Tree in the appropriate Cummins Service Manual.
DTC 65­24

Engine Torque Verification at Neutral

Description: This DTC is logged when there is a large deviation (greater than 500 N∙m) between reported and
estimated engine torque while in Neutral. This condition will inhibit Neutral to range shifts. Either the engine is
not producing enough torque or the engine is producing too much torque.
Service: There may not be an ECM code associated with this condition. Refer to the Engine Performance
Troubleshooting Tree in the appropriate Cummins Service Manual.

Copyright © 2013 Allison Transmission, Inc. All Rights Reserved.

#1707, Rev. C
August, 2013
Page 4 of 12
DTC 65­25

Engine Failed to Crank

Description: This DTC is logged if the engine is unable to increase its speed by 25 rpm above the engine cranking
speed of 600 rpm (above 32°F transmission sump temperature) or 820 rpm (below 32°F transmission sump
temperature), after 10 seconds of cranking. The maximum engine cranking duration is 30 seconds.
Service: Refer to the Engine Performance Troubleshooting Tree in the appropriate Cummins Service Manual.
Refer to Allison SIL 2­EP­07 and Troubleshooting Manual TS3715EN.
DTC 65­26

Engine Performance

Description: This DTC code is logged when the engine is not producing the requested torque as measured by the
H 40/50 EP SystemTM. The H 40/50 EP SystemTM will respond by reducing system performance (output torque)
in proportion to the engine performance reduction.
There are three conditions that will log this code:
Condition 1: Engine has a problem that is diagnosable (e.g. High engine temperature, low oil pressure) and
cannot produce the requested engine torque. Since this condition is diagnosable, the engine still reports
the actual engine torque to the hybrid system. In most cases, the ECM will have logged a Fault Code.
Retrieve the engine Fault Code(s) and refer to the Fault Code troubleshooting tree(s) in the appropriate
Cummins Troubleshooting and Repair manual.
Condition 2: The engine has a problem that is NOT diagnosable by the ECM (e.g. Low fuel pressure,
sticking/damaged exhaust brake valve) and cannot produce the torque requested by the hybrid system. The
ECM may not log a Fault Code under these conditions. Refer to the Engine Performance Troubleshooting
Tree in the appropriate Cummins Service Manual.
Condition 3: Engine has a problem that is NOT diagnosable (e.g. damaged injectors) and cannot produce the
engine torque requested by the hybrid system. This condition is NOT diagnosable and the engine reports the
incorrect engine torque to the hybrid system. There will not be an ECM code associated with this condition.
Refer to the Engine Performance Troubleshooting Tree in the appropriate Cummins Service Manual.
Condition 3 Note: This DTC is different from 65­23: Engine Torque Verification diagnostic. The Engine Torque
Verification fault logic is insensitive to minor and medium engine torque reduction problems and only detects
when there is a major torque reduction/increase from the engine (greater than 500 N∙m).

Allison DOC® for PC–Service Tool (H 40/50 EPTM) Troubleshooting Techniques:
Allison DOC® for PC–Service Tool (H 40/50 EPTM) can be used to view Requested Engine and Actual Engine
Output Torque and Speed. Using the Strip Chart function, the parameters can be plotted and reviewed to assist in
diagnosing vehicle low power complaints.
Recording a Snapshot with Allison DOC®:
Connect the laptop and necessary communication hardware to the vehicle diagnostic port.
1. Launch Allison DOC® for PC–Service Tool (H 40/50 EPTM) by double clicking the icon on the desktop.
2. Connect to the vehicle and press F6 (Fire Trigger) to begin recording.
3. Operate the vehicle while in range until the code becomes active or the low power condition is experienced.
4. Press F7 (Stop Recording) and save the Snapshot for replay and analysis.
Playback of a Snapshot with Allison DOC®:
1. Launch Allison DOC® for PC–Service Tool (H 40/50 EPTM) by double clicking the icon on the desktop.

Copyright © 2013 Allison Transmission, Inc. All Rights Reserved.

#1707, Rev. C
August, 2013
Page 5 of 12
2. Select the Snapshot / Playback / Open Playback File feature on the top toolbar and open the Snapshot
previously saved.
3. Select the Diagnostic button or press F3 and select Strip Chart. The Strip Chart Configuration screen
will appear.
4. Scroll to the Engine Information category, and highlight the parameters desired (i.e. Requested Engine
Torque, Actual Engine Torque). Select the Add button to add the desired parameters to the graph.
5. Once parameter selection is complete, select the OK button to plot the Strip Chart.
6. Monitor Actual Engine performance vs. Requested Engine performance. Under normal circumstances the
Actual Engine Torque will meet the Requested Engine Torque with some initial lag due to turbo spool
up. Figure 1 provides a representation for a typical Requested Engine Torque vs. Actual Engine Torque
acceleration scenario.
7. When Actual Engine Torque does not meet the Requested Engine Torque, vehicle performance will be
degraded and H 40/50 EPTM output torque will be reduced. Figure 2 provides a representation for a typical
Requested Engine Torque vs. Actual Engine Torque acceleration scenario where the engine is not capable of
providing the requested torque.

Figure 1. Allison DOC® Strip Chart of Engine Meeting Hybrid Torque Request

Copyright © 2013 Allison Transmission, Inc. All Rights Reserved.

#1707, Rev. C
August, 2013
Page 6 of 12

Figure 2. Allison DOC® Strip Chart of Engine Not Meeting Hybrid Torque Request
Customer Adjustable Engine Parameter Settings:
There are many customer adjustable parameters within the electronic control unit of heavy­duty engines. Several
of these impact the operation of the H 40/50 EP SystemTM. They must be set appropriately for optimal performance
of the entire vehicle propulsion system. Engine settings for these customer adjustable parameters that affect the H
40/50 EP SystemTM operation are provided below by engine model year. These lists do not contain all the customer
adjustable parameters for the given engine but only those that impact the operation of the H 40/50 EP SystemTM.
The remaining parameters are to be assigned by the vehicle OEM or the end­user customer.
CAUTION: For H 50 EP SystemTM installations, the Customer Adjustable Engine Parameters and Values
must be set exactly as shown in the table below. If the engine parameters and values are not set as
shown, system performance may be affected or system damage could occur. Do NOT modify the listed
parameters and values for use with other vehicle systems.

Copyright © 2013 Allison Transmission, Inc. All Rights Reserved.

#1707, Rev. C
August, 2013
Page 7 of 12
Table 2. Cummins ISB and ISL (2013)
Accelerator Interlock

Disable

Adjustable Low Idle Speed
Low Idle Speed

700 or 750 rpm (must be same as CSS selection)

Low Idle Speed Adjustment Switch

Disable

Aftertreatment
Aftertreatment Diesel Particulate Filter
Diesel Particulate Filter Regeneration Permit Switch

Enabled (for vehicles with HUSHTM mode; otherwise, no
preference)

Alternator Failure Warning
Alternator Speedup

Disable

Clutch Pedal Position Switch

Not Installed

Cruise Control

Disable

Cruise Control and Engine Brake Interaction

Disable

Engine Brake Control
Delay Time

0.0 Seconds

Engine Brake Type

Exhaust Brake OR Variable Geometry Turbo

Minimum Vehicle Speed

0.0 mph

Clutch Pedal Activation

Disable

Service Brake Activation

Disable

Fan Control
Fan on With Engine Brake

Disable

Fast Idle Warm­up

Disable

Gear Down Protection

Disable

Governor Type
Governor Type

Automotive

Governor Type Switch

Disable

Idle Shutdown

Disable (refer to 6.6)

J1939 Controls
J1939 Stop Broadcast Allowed

Disable

Powertrain Protection

Disable

PTO

Disable

Road Speed Governor
Maximum Accelerator Vehicle Speed

Set to 130 mph or maximum allowed

Maximum Vehicle Speed

Set to 130 mph or maximum allowed

Switched Maximum Vehicle Speed

Disable

SAE J1939 Multiplexing

Copyright © 2013 Allison Transmission, Inc. All Rights Reserved.

#1707, Rev. C
August, 2013
Page 8 of 12

Table 2. Cummins ISB and ISL (2013) (cont’d)
Accelerator Pedal or Lever Position

Enable

Source Address

3 ­ Transmission #1

Aftertreatment Regeneration Permit Switch

Disable (Enable only for vehicles with HUSHTM Mode)
3 – Transmission #1 * (only for vehicles with HUSHTM Mode)

Source Address

Enable (only for vehicles with HUSHTM Mode)

Auxiliary Shutdown Switch
Source Address

3 ­ Transmission #1
Enable for vehicles that are configured to "Use engine cooling
fan for auxiliary braking" and/or have the transmission cooler
stacked with the engine cooler (Vehicle Fan Configurations 1
& 2 on the CSS form)

Fan Control Switch

Source Address

3 ­ Transmission #1

Idle Validation Switch

Enable

Source Address

3 ­ Transmission #1

Switched Maximum Engine Operating Speed

Disable

Transmission Setup
Top Gear Transmission Ratio

0.5

Transmission Type

Automatic