TSB210020-011320

1/31/22, 4:53 PM
Allison Transmission® Fault P2637 Caused by Engine Control Module (ECM) Calibration
Technical Service Bulletin
Technical Service Bulletin: TSB210020
Released Date: 13-Jan-2022
Allison Transmission® Fault P2637 Caused by Engine Control Module (ECM)
Calibration
Allison Transmission® Fault P2637 Caused by
Engine Control Module (ECM) Calibration
Warranty Statement
The information in this document has no effect on present warranty coverage or repair practices,
nor does it authorize TRP or Campaign actions.
Contents
Product Affected
B6.7 CM2450 B155B
L9 CM2350 L116B
L9 CM2350 L123B
L9 CM2450 L126B
X15 CM2350 X114B
X15 CM2350 X116B
X15 CM2450 X124B
X15 CM2450 X134B
Issue
Symptom:
CHECK TRANSMISSION lamp is illuminated
Shift quality issues and gear limitation
Active or inactive Allison Transmission® fault P2637
Root Cause:
Engine control module (ECM) calibration code
Verification
Verify Allison Transmission® fault code P2637 is active or has inactive counts.
Compare the ECM code and revision number in the ECM to the calibration revision listed in
the ECM calibration revision history on QuickServe® Online (QSOL) for applicable changes.
https://quickserve.cummins.com/qs3/pubsys2/xml/en/tsb/2021/tsb210020.html
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1/31/22, 4:53 PM
Allison Transmission® Fault P2637 Caused by Engine Control Module (ECM) Calibration
Resolution
Cummins Inc. is releasing ECM calibration revisions that reduce occurrences of Allison
Transmission® fault P2637. Timing availability of the ECM calibration improvement will vary by
engine service model name. See Table 1 below.
If an ECM calibration update for this issue is available, the ECM calibration revision must be
that revision or higher.
If ECM calibration revision is not yet available for one of the listed engine service model
names, cycling the key can temporarily extinguish the CHECK TRANSMISSION lamp and
return the vehicle to normal operation until the fault comes active again.
If the ECM already contains the ECM calibration improvement for P2637, reference the OEM
or Allison Transmission® service processes.
Table 1, ECM Calibration Code Availability
Service Model
Name
P2637 Calibration
Improvement
Available
Production
Implementation
Date
QuickServe® Online
(QSOL) ECM
Calibration Code
Date
B6.7 CM2450 B155B
Yes
6 August 2021
16 July 2021
L9 CM2350 L116B
Pending
-
-
L9 CM2350 L123B
Pending
-
-
L9 CM2450 L126B
Yes
15 March 2021
15 February 2021
X15 CM2350 X114B
Yes
18 October 2021
14 October 2021
X15 CM2350 X116B
Yes
18 October 2021
14 October 2021
X15 CM2450 X124B
Yes
1 January 2021
11 May 2021
X15 CM2450 X134B
Yes
17 December 2021
15 December 2021
Document History
Date
Details
2021-1-29
Module Created
2021-6-25
Updated Table 1 for X15 CM2450 X124B.
2021-11-18
Non-Product Problem Solving (PPS)
Last Modified: 13-Jan-2022
https://quickserve.cummins.com/qs3/pubsys2/xml/en/tsb/2021/tsb210020.html
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