Solution K31280406
Tuesday, March 6, 2018 5:26:02 PM CET

Solution
Title (customer effect)

Diagnostic Trouble Code ( DTC ) P26E8 Intermittently Lighting The Malfunction
Indicator Lamp ( MIL ); Possible Derate Warning - OBD13 And Newer Chassis

Cause

P26E8 - Actuator Supply Voltage "D" Circuit Low may set in US13 and newer chassis
and can be accompanied by a derate warning in the Driver Information Display ( DID ).
The fault may be difficult or not possible to duplicate and will likely also result in No
Fault Found (NFF) from Guided Diagnostics (GD).

Solution

Overview
The diagnostic process that sets P26E8 monitors voltage level to the Inlet and Outlet
NOx Sensors, the PM Sensor, and the DEF Quality (Level and t0emperature) Sensor. If
voltage to the sensors drops below the monitored threshold for a long enough period, an
occurrence of P26E8 will log. This condition will most often occur only when power
demand from all four sensors is at maximum level in the same timeframe. There may be
a driver report of a 30 minute derate warning accompanying the code. Due to how
specific conditions have to be to cause the code to log, P26E8 will likely appear inactive
on a DTC Readout, and Guided Diagnostic steps often result in No Fault Found.
P26E8 will also be accompanied by DTCs for communication loss with all of the
concerned sensors ( U029D, U029E, U02A2, U02A3 ) since they will be offline during
the period that voltage is below threshold.

Repair
1. Assure that the 12 volt DC power connections from the battery, to the fuse(s), to the
Aftertreatment Control Module ( ACM ) connector are good by taking them apart where
possible and looking for a loose connection. Clean all connection points as necessary.

2. Do the same from the battery negative connections. All connectors between the
batteries and the ACM should be inspected.

- Take apart and clean the frame ground stud connection.

3. Thorougly check the ACM connector to ensure there is no damage or corrosion that
may contribute to a poor connection.
4. Ensure all of the batteries pass a load test.
The goal of these activities is to ensure that the highest voltage possible is supplied to
the ACM.

If The Chassis Returns Multiple Times For P26E8
1. Perform all of the above steps.
2. Replace the ACM.

Solution visibility

Dealer distribution

Function(s)/component(s) affected
Function affected

DEF Dosing , SCR , battery/power supply , wiring harness , 1 1 0 EMS , 2 1 0 ACM
, Diagnostic tool

Function Group
Function Group

258 emissions after-treatment , 286 engine wires and mounting parts , 31 battery;
energy storage system; mounting parts , 37 cable; fuse

Customer effect
Main customer effect

regeneration , power supply , diagnostics/methodology , efficiency/abnormal behavior
, fault code/display

Fault code(s)
OBD 2013 Diagnostic
Trouble Codes

U029D , U029E , U02A2 , U02A3

Conditions
Vehicle operating mode
Frequency of occurrence of
problem

when driving , when stationary
random

Administration
Author

UT5061H

Dealer ID

UT5061H

Last modified by

RU4469V

Creation date

11-01-2018 14:01

Date of last update

02-02-2018 15:02

Status

Published

Average score

0

Number of scores

1

NA_MACK_Vehicle_Range
NA_MACK_Vehicle_Ran
ge

Cabover , Conventional

NA_VOLVO_Vehicle_Range
NA_VOLVO_Vehicle_Ra
nge

Engine family

Conventional

Engine family

11L Engine , 13L Engine , MP7 , MP8