How Volvo D13 and Mack MP8 fault codes work
The Volvo D13 and the Mack MP8 are the same 12.8-liter engine with different badges and tuning, so they share fault codes and failure patterns. Older trucks show faults as MID/PID/PPID/SID/FMI on the cluster; newer ones show SPN/FMI. Either way, amber check engine means service soon and red stop means pull over. The most common families are aftertreatment, EGR, turbo and coolant.
One engine, two badges
Volvo Group builds the D13 for Volvo VNL and VNR and the MP8 for Mack Anthem, Pinnacle and Granite. Same block, same aftertreatment layout, same control software family. What differs is the cluster layout and the telematics brand name.
Seeing a light on the dash? Snap it with DERATE and know if you can keep driving
Reading the codes: MID/PID vs SPN/FMI
Trucks built roughly before 2014 use the older SAE J1587 format. The Volvo VNL manual defines it like this:
- MID (Message Identifier) is the module talking. MID 128 is the engine ECM, 130 the transmission, 136 ABS, 140 the cluster, 144 the vehicle ECU.
- PID (Parameter Identifier) or SID (Subsystem Identifier) names the sensor or component. PID 110 is coolant temperature, PID 100 oil pressure, PID 103 turbo speed.
- PPID and PSID are the Volvo-proprietary versions. PPID 329 is the aftertreatment fuel injector, the "7th injector".
- FMI is the failure type, as on J1939: 3 and 4 wiring, 7 mechanical not responding, 12 bad device.
On the older cluster, scroll to Diagnostics, pick the module, and press Set to toggle between plain text and raw MID/PID/FMI. The display also shows ACTIVE or INACTIVE and a count. Newer VNL and Anthem clusters show SPN/FMI, for example SPN 3364 FMI 18 for DEF quality, and a text line. Photograph both.
Common code families on D13 and MP8
Aftertreatment: DEF, DPF and the 7th injector. Volvo and Mack use an AHI (aftertreatment hydrocarbon injector), the 7th injector, to dose fuel into the exhaust for a regen. When it cokes up you get failed regens, a DPF lamp that will not clear, and codes on PPID 329 or the shut-off valve on PPID 328. DPF pressure codes show as SPN 3251 on newer trucks. DEF codes cover level, quality (SPN 3364) and SCR efficiency. Inducement is staged: warning, torque reduction, then a speed limit, historically ending at 5 mph (8 km/h). Software updates following the EPA's 2025 revised guidance are raising final inducement speeds across the industry, so ask the dealer what your truck has. See /guides/def-fault-codes-explained and /guides/dpf-regeneration-guide.
EGR. The D13 EGR valve and cooler are known wear items. Valve codes read as SID 146 on older trucks. Symptoms: rough idle, white smoke on cold start when the cooler leaks, and a MIL. Guide: /guides/egr-valve-and-cooler-problems.
Turbo. The D13 and MP8 use a VGT with a smart actuator. Turbo speed and position codes (PID 103, actuator codes) bring low power and a derate. A failed actuator is typically 1,500 to 2,500 dollars installed. See /guides/turbo-failure-signs.
Coolant. PID 110 or SPN 110 FMI 0 is coolant temperature high. Red lamp, stop now. Check the EGR cooler, the radiator cap and the fan clutch. See /code/spn-110-fmi-0.
Oil pressure. PID 100 or SPN 100 FMI 1 is low oil pressure. Engine protection cuts torque and, on severe faults, shuts the engine down after a warning. Do not restart until the level and sensor are checked.
Keep driving or stop
- Keep driving, book service: single amber lamp, EGR or NOx sensor code, inactive counts only.
- Caution, shop today: DEF quality or SCR efficiency code, DPF lamp solid, 7th injector code with failed regens.
- Stop now: red stop lamp, coolant temperature or oil pressure, flashing lamp, or a speed limit already active.
Volvo Uptime Center and Mack GuardDog Connect
Both brands use the same 24/7 Uptime Center in Greensboro, North Carolina. Volvo calls the service Remote Diagnostics, Mack calls it GuardDog Connect. When a critical fault code sets, the truck sends it with data from before and after the event. Agents review it while you are still rolling. If it needs attention, Mack OneCall or Volvo Action Service contacts the fleet, finds a dealer with parts in stock, and pushes repair instructions through ASIST before you arrive. Volvo claims this cuts diagnostic time by up to 70 percent. Nothing is fixed remotely.
What to check first
- Photograph the lamps and the fault screen, text and numbers.
- Check DEF level and the last fill, coolant level when cool, and oil level.
- If the DPF lamp is on and regens keep failing, note how many attempts. That tells the shop whether the 7th injector or the DPF itself is the problem.
- Run the photo through DERATE, an iPhone app that reads a picture of the dash warning lights or a scanner screen and gives a free keep-driving, caution or stop verdict. The detailed causes, steps and cost come with a plan.
- With a red lamp or an inducement message, head to a Volvo or Mack dealer with Premium Tech Tool, which resets the inducement after the repair.
Costs vary by shop and region. 7th injector: about 400 to 900 dollars installed. DEF pump: typically 1,200 to 2,500 dollars. EGR cooler: about 2,000 to 4,000 dollars. DPF clean: 300 to 600 dollars.
FAQ
Are Volvo D13 and Mack MP8 fault codes the same?
Yes. Same engine, same software family, same codes. The cluster text and telematics brand differ, the fault behind them does not.
What is MID 128 on a Volvo truck?
MID 128 is the engine ECM. A code listed under MID 128 came from the engine, not the transmission (MID 130) or the ABS (MID 136).
Will GuardDog Connect or Remote Diagnostics clear my code?
No. They send the fault to the Uptime Center and help schedule repair and parts. The code is cleared at the dealer after the fix.