This is the PACCAR MX EPA 2013 DTC diagnostic service manual, a technical reference published by PACCAR for troubleshooting back pressure valve actuator faults in PACCAR MX engines. The 8-page document provides step-by-step repair procedures, electrical schematics, component checks, and verification cycles for mechanics diagnosing active or inactive fault code P1021 related to BPV actuator CAN communication errors.
The manual covers the complete P1021 fault condition set when the BPV actuator (L096) detects a missing cyclic CAN command message from the PCI ECU (D420) lasting more than 2 seconds. It includes technical data on the back pressure valve assembly, component location, wiring harness connector pinouts, and the fail-safe operation that moves the BPV valve to fully open (100% position) when communication is lost.
Document details and specifications — PACCAR MX EPA
| Brand | PACCAR |
| Model coverage | PACCAR MX Engines (EPA2013) |
| System/Group | DTCs / MX Engines (EPA2013) |
| Publication no. | P1021 |
| Year/Revision | 2013 |
| Pages | 8 |
| File size | 0.7 MB |
| Format | |
| Language | English |
Table of contents
- Code number P1021 – Fault code description and information
- Description of components – Back pressure valve (BPV) actuator (L096)
- BPV actuator control system and E-CAN communication
- Unpowered and fail-safe position specifications
- Effect on system – Exhaust heating, EGR flow, engine braking, and VTG turbo control
- Location of component(s)
- Diagnostic condition and set/reset conditions
- Electrical diagram(s) with wiring harness connector pinouts
- Technical data – Component check for BPV valve (L096)
- Wiring check procedure with resistance measurements
- Possible causes and additional information
- Diagnostic Step-by-Step troubleshooting tree (5 steps)
- Step 1 – Key-cycle procedure
- Step 2 – Visual inspection of BPV valve connections and wiring
- Step 3 – Electrical checks for CAN connection and power supply
- Step 4 – Try another BPV valve to isolate the fault
- Step 5 – Reset DTCs and verify repair
- Repair verification and drive cycle procedures
Applies to these models
This PACCAR MX EPA 2013 manual applies to PACCAR MX diesel engines equipped with EPA 2013 emission control systems, including back pressure valve actuators, E-CAN communication networks, and PCI ECU control modules. It covers diagnostic and repair procedures for fault code P1021 occurring on heavy-duty trucks using PACCAR MX powertrains. For official PACCAR technical resources and engine support, visit PACCAR official.
Who needs this PACCAR MX EPA 2013 manual
Heavy-duty truck mechanics, diagnostic technicians, and workshop owners servicing PACCAR MX engines need the PACCAR MX EPA 2013 manual to accurately diagnose and repair back pressure valve actuator faults. This guide is essential for technicians requiring detailed electrical schematics, component testing procedures, and systematic troubleshooting steps to isolate CAN communication failures and confirm actuator replacement.
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