Dodge and Ram: common OBD-II codes and Chrysler-family quirks

Dodge and Ram share their electrical architecture, modules and much of their powertrain with Jeep and Chrysler. Fault patterns transfer directly between the badges, and so do the fixes.

Companion reading: Jeep and Chrysler common DTC codes.

The architectural quirk worth knowing

Chrysler-group vehicles route a great deal through a small number of central modules — historically the TIPM (Totally Integrated Power Module) and the body control module. That is efficient, and it has a consequence: a single module fault produces symptoms that look like several unrelated failures at once.

Fuel pump not priming, wipers running on their own, horn sounding by itself, lights behaving oddly — those together are a module or power distribution problem, not four separate faults.

The diagnostic discipline that follows: scan every module and record the full code set before clearing anything. A cluster of communication codes points at power, ground or the network rather than at each individual system.

U0100 lost communication with ECM, U0140 and U0155 body and cluster, B1000 body control codes and when the scanner lies about ghost codes.

Test the battery under load first. Low voltage on a vehicle with this many modules manufactures codes in quantity.

Recurring powertrain codes

P0300 and cylinder misfires

Coils and plugs, as everywhere. On the Pentastar V6, a cylinder head issue affecting one bank was a known concern on early examples — a persistent single-cylinder misfire on that engine that survives the swap test deserves a compression check rather than another coil.

P0301 to P0304 and P0300.

P0016 and timing

Chain and phaser wear on higher-mileage V6 and V8 engines. A cold-start rattle is the early warning: P0016 correlation and VVT P0011 and P0014.

Oil condition is the common root cause — engine oil viscosity and approvals.

P0171 and P0174 — lean

Intake gaskets and PCV systems. Fuel trims at idle versus 2500 rpm settle leak against metering: P0171 and P0174.

P0420 and P0430 — catalyst

Common at higher mileage, and frequently misdiagnosed. Rule out an exhaust leak near the downstream sensor and an ageing upstream sensor first: P0420, P0430 bank 2 and P0133.

EVAP

Purge and vent valves, and canisters exposed underneath the vehicle. P0442 and P0440 and P0446.

Transmission

The 8-speed automatics used across the range are generally robust, and most complaints trace to fluid condition or specification rather than internals. Harsh engagement after a service is very often the wrong fluid.

P0700 is only a pointer — read the TCM for the real code. Then: P0730 incorrect gear ratio, P0740 and P0741 and ATF diagnostics.

Symptom-led: clunk when shifting into drive and gears slipping on an automatic.

Ram diesel: the Cummins

The 6.7 Cummins in Ram heavy-duty trucks adds a full emissions stack — DPF, SCR and the associated sensors.

• DPF and soot load — DPF light on and P2002 and P2463.
• AdBlue and SCR — AdBlue system diagnostics and AdBlue warning countdown.
• Fuel rail pressure under load — P0087.

These trucks are bought to tow, and towing is exactly what stresses the emissions system and the transmission. Watch transmission fluid temperature on long pulls: transmission overheating warning and towing an automatic.

Four-wheel drive and diffs

Transfer case and differential oils are routinely never changed on trucks that spend their lives towing. Whine that varies between acceleration and overrun is gear mesh, and an oil change at that stage sometimes prevents a rebuild: differential and transfer case care and whining noise when accelerating.

Imported examples

Many of these vehicles reach other markets through salvage auctions or private import. Two things to check beyond the usual:

• Airbag status. Deployed systems that were reset rather than replaced are a genuine risk — airbag light on causes.
• Whether all monitors are ready, which tells you whether the clean scan you were shown means anything.

US salvage import OBD diagnostics, import car, what to check and OBD-II vs EOBD vs JOBD.

Try it on the free tier of the app — pair an ELM327 adapter and check battery voltage and the full code set across modules before diagnosing anything individually. On a Chrysler-family vehicle, that order saves the most time.