P1429 on 2007-2013 Mini Cooper S: DMTL Pump Failure Causes and Fixes

What's Unique About the 2007-2013 Mini Cooper S

For the R56 generation Mini, the DMTL pump is mounted near the right rear wheel, making its wiring harness highly susceptible to corrosion from road salt and moisture, and damage from debris. In fact, Mini acknowledged the high failure rate by issuing a warranty extension (TSB M01 05 11) for the DMTL pump on many of these models to 10 years or 120,000 miles. It's crucial not to confuse this with the P1429 definition for other brands like Peugeot, which can relate to a Diesel Particulate Filter (DPF) pressure sensor on their diesel models.

Generation note: The 2007-2013 Mini Cooper S is the R56 generation. The N14 engine was used from 2007-2010, and the N18 engine from 2011-2013. The DMTL pump system and the P1429 fault are common to all models within this year range, as well as other R55 and R57 models.

Symptoms You May Notice

• Check Engine Light is on
• Vehicle will fail an emissions inspection
• Possible fuel odor if a significant leak is present in the EVAP system.

Most Likely Causes

1. Corroded or Damaged DMTL Pump Wiring Harness 🔴 High Probability The pump and its connector are located in a vulnerable position ahead of the right rear wheel, where they are exposed to road salt, water, and debris. This leads to corrosion and wire damage, a very common issue in winter climates. Some specialists estimate wiring issues account for 75% of DMTL-related faults on this platform.
   How to confirm: Visually inspect the wiring harness and 3-pin connector leading to the DMTL pump. Look for green or white corrosion, chafed wires, or breaks in the insulation. Wires can break inside the insulation right at the connector, so gently tug on each wire.
   Typical fix: Repair the damaged section of the wiring harness or replace the connector pigtail. The repair pigtail part number is often cited as 61132359998 for BMW/Mini applications.
   Est. part cost: $20-$40
2. Failed DMTL Pump 🔴 High Probability The part had known durability issues, leading Mini to issue a warranty extension (TSB M01 05 11) for many affected vehicles. The internal motor or heater element can fail over time.
   How to confirm: If the wiring is confirmed to be good, the pump itself is the likely culprit. A scan tool with manufacturer-specific functions, like Autologic's AssistPlus, can command the DMTL pump to run a system test 🎬 Watch: How to test the DMTL pump on R56 models to confirm its operation. Without a specific scan tool, the next logical step after verifying wiring is to replace the pump.
   Typical fix: Replace the DMTL pump. It is mounted to the charcoal canister via a bracket. The job takes about 30 minutes. 🎬 See this walkthrough for replacing a faulty DMTL pump
   Est. part cost: $70-$100
3. Saturated Charcoal Canister ⚪ Low Probability Consistently over-filling the fuel tank (i.e., continuing to pump fuel after the nozzle clicks off) can force liquid gasoline into the charcoal canister, which is designed only for vapor. This can damage the canister and, subsequently, the attached DMTL pump by forcing fuel into it.
   How to confirm: Remove the charcoal canister and check if liquid fuel drips out or if it feels unusually heavy. The canister should only contain vapor.
   Typical fix: Replace the charcoal canister and the DMTL pump. Avoid topping off the fuel tank in the future.
   Est. part cost: $150-$250

Diagnosis Steps

1. Read the fault codes with an OBD-II scanner to confirm P1429 is present. Note any other specific Mini codes like 2733-2736.
2. Safely raise and support the rear of the vehicle. A floor jack and jack stands are sufficient.
3. Locate the DMTL pump and charcoal canister assembly. It is found inside the plastic wheel well liner, forward of the right rear wheel.
4. Carefully inspect the 3-pin electrical connector and wiring harness going to the DMTL pump. Look for any signs of corrosion (green/white powder), chafing, or broken wires. Gently pull on each wire at the connector to check for internal breaks.
5. If wiring damage is found, repair it using a pigtail connector kit (e.g., part number 61132359998) or by soldering in new wire sections and using heat shrink tubing. Clear the codes and drive the vehicle to see if the code returns.
6. If the wiring appears intact, the DMTL pump is the most likely cause. Disconnect the electrical connector and the two vapor lines. Unbolt the pump from its bracket on the charcoal canister and install the new one.
7. When replacing the pump, it is also recommended to replace the rubber grommet that seals the pump to its filter, part number 16131183912.
8. After replacement, clear the fault codes. The EVAP system monitor may need to complete a drive cycle to confirm the fix. A specialized scan tool can force the DMTL test to run immediately to verify the repair.

Parts You'll Likely Need

• Leak Diagnosis Pump (DMTL) (OEM #16137193479) — This pump is a known failure item, to the point that Mini extended its warranty. It is the component responsible for the test that triggers code P1429. The Bosch-manufactured part is identical to the Genuine Mini part.
  Trusted brands: Bosch
  OEM price range: $150-$240
  Aftermarket price range: $70-$100
• DMTL Pump Connector Pigtail (OEM #61132359998) — Due to its exposed location, the wiring harness connector often corrodes before the pump fails. Repairing the harness is a common first step.
  Trusted brands: BMW/Mini Genuine
  OEM price range: $25-$45
  Aftermarket price range: $15-$30
• DMTL Pump Grommet (OEM #16131183912) — This small rubber grommet seals the pump to its filter/inlet. It often becomes brittle and should be replaced whenever the pump is serviced to ensure a proper seal.
  Trusted brands: Genuine Mini
  OEM price range: $6-$10

Related Codes That Often Appear With This One

• 2733, 2734, 2735, 2736 — These are BMW/Mini specific fault codes that point directly to 'DMTL, module error' and are often stored alongside the generic P1429 code, as noted in the official TSB.

Technical Service Bulletins (TSBs) & Recalls

• M01 05 11 - Extended warranty coverage for the Tank Leak Diagnostic Module (DMTL) pump to 10 years/120,000 miles on affected models due to durability issues. It covers R55, R56, and R57 models and instructs dealers to replace the pump if codes 2733, 2734, 2735, or 2736 are stored.

Platform-Specific Known Issues

• Mini issued Service Information Bulletin (SIB) M01 05 11, extending the warranty on the DMTL pump to 10 years or 120,000 miles for many R55, R56, and R57 models due to high failure rates. The TSB instructs dealers to replace the pump if specific DMTL fault codes (2733-2736) are present, without performing further test plans.

Mechanic-Grade Diagnostic Values

• DMTL Pump Motor Current Draw — expected: The DME (engine computer) monitors the pump's amperage draw as its primary diagnostic metric. During a system test, the current should change as the pump pressurizes the system against a known reference orifice. A healthy pump will show a distinct current signature. For example, a reference leak test might show a current of ~26 mA.. Failure: An open circuit in the pump motor or wiring will result in zero current draw. A short circuit or a seized motor can cause excessively high current draw, triggering codes like P1449 or 3225. If the current draw during the system test is too low, it indicates a leak in the system.
• Voltage at DMTL Pump Connector — expected: The 3-pin connector should have: Pin 1: Battery Voltage (12V+), Pin 2: Ground (continuity to chassis), Pin 3: Control Signal from the DME. Wires are typically Red/Violet (power) and Brown/Black (ground).. Failure: Absence of 12V power or ground with the key on points to a wiring issue (corrosion, break) or a blown fuse upstream. The most common failure is a loss of continuity at the connector pins due to corrosion.

Hidden / Shadow Codes Worth Checking

• 273C: DMTL pump, heater, activation: Open circuit. This is a very specific code pointing to the heater element within the DMTL pump assembly. (see via BMW/Mini-specific scan tool like ISTA or a high-end professional scanner.)
• P1447 / 2A18 / P1449: DMTL Pump Current Too High. This indicates the pump motor is drawing too much amperage, often due to an internal short circuit or being saturated with liquid fuel. (see via OBD-II scanner or BMW/Mini-specific tool.)
• P2A12 / P2A13: DMTL solenoid valve, control / DMTL Leak Diagnosis Pump, control. These codes indicate a control circuit fault for the pump or its internal solenoid. (see via OBD-II scanner or BMW/Mini-specific tool.)
• 3225: DMTL short at pin B+. This points to an electrical short circuit on the power supply wire to the pump. (see via BMW/Mini-specific scan tool.)

Scan Tool Commands That Help

• ISTA (BMW/Mini Dealer Software) or equivalent (Autologic, etc.): Diagnose Module for Tank Leaks / DMTL pump activation — This is the primary and correct method for diagnosing the DMTL system. It commands the pump to run through a multi-stage test (reference leak, minor leak, micro leak) while the DME monitors the pump's current draw to verify its function and seal the system. This test confirms if the pump is working electrically and can hold pressure, avoiding misdiagnosis from improper smoke testing.

Wiring & Ground Locations

• DMTL Pump Connector — Forward of the right rear wheel, attached to the DMTL pump on the charcoal canister. You must remove the plastic wheel arch liner to access it.. This is the single most common failure point. The connector's pins and the wires leading into it are highly prone to corrosion from road salt and water, causing an open or short circuit that triggers P1429.

Real Owner Repair Stories

• Bimmerpost forum user (BMW E92 (shares DMTL system design with Mini)) — SES Light with codes P2A13, P2A12, P2A18. Codes would return immediately after clearing.
  ❌ Tried (didn't work) Replacing the DMTL pump, Replacing the gas cap, Inspecting the common wire chafe area in the wheel well
  ✅ What actually fixed it Found a disintegrated wire about 6 inches *higher* in the harness than the typical chafe point. Splicing in a new section of wire resolved the issue permanently.
• North American Motoring forum user (2007-2009 Mini Cooper S with ~50k miles in New York) — Check Engine Light
  ✅ What actually fixed it Dealer diagnosis found significant salt corrosion on the DMTL pump and its wiring harness. Both the pump and harness had to be replaced to fix the problem, confirming the vulnerability in salt-belt regions.

"I Checked Everything" — The Actual Cause

• A BMW Technical Information System (TIS) document explicitly warns technicians NOT to use a standard smoke test (Evaporative Leak Test Tool) to diagnose DMTL-related faults. Applying external pressure can force the pump's internal check valve open, creating a leak where none exists and leading to the incorrect conclusion that another component is faulty. The only correct procedure is to use a BMW-compatible scan tool to run the internal DMTL test plan, which uses the pump itself to generate pressure and measure current.

OEM Part Supersession History

• 16136752551, 16136764191 → 16137193479 — Part has been updated over the years to improve durability and reliability, addressing the high failure rate that led to the warranty extension.

Model Year Variations Within This Range

• 2007-2013: While the N14 (2007-2010) and N18 (2011-2013) engines have significant mechanical and electronic differences, the DMTL pump, its location, and its common failure modes (wiring corrosion, pump failure) are consistent across the entire R56 generation. The problem is tied to the chassis design, not the engine version.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Timing Chain Tensioner Failure ('Death Rattle') 🔴 High — Very common on N14 engines, especially pre-2011 models. Can occur as early as 30,000-50,000 miles. Characterized by a loud rattling noise on cold starts. (Ref: Mini had service campaigns to inspect and replace timing chain components (e.g., SIM-11-05-12).)
• High-Pressure Fuel Pump (HPFP) Failure 🔴 High — Common failure item, often occurring between 40,000 and 70,000 miles. Symptoms include long cranks, rough idle, hesitation, and limp mode (P2880 code). (Ref: Mini issued a warranty extension for the HPFP on many N14-equipped vehicles.)
• Intake Valve Carbon Buildup 🟠 Medium — Inevitable due to the direct-injection design. Significant buildup causing rough idle, misfires, and poor performance is common every 40,000-50,000 miles.
• Excessive Oil Consumption 🟠 Medium — Many N14 engines consume oil at a high rate (e.g., 1 quart per 1,000 miles) due to PCV system design and piston ring wear.
• Thermostat Housing & Water Pump Leaks 🟠 Medium — The plastic thermostat housing and water-pipe are prone to cracking and leaking coolant, often after 50,000 miles. The water pump can also fail. (Ref: A class-action settlement led to a warranty extension for the water pump on some models (Herremans v. BMW).)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used wiring harness pigtail from a dry-climate, corrosion-free donor car is a cost-effective and reliable repair. A used DMTL pump is a significant gamble due to the part's known high failure rate and should generally be avoided.

Donor-vehicle mileage cap: roughly under 60000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a wiring pigtail: Check for absolutely no green or white powder on the connector pins.
• Ensure the plastic connector housing and locking tab are not brittle or broken.
• Confirm the wire insulation is flexible and not cracked or chafed.

OEM-only on this vehicle (don't cheap out):

• None for this repair. The OEM supplier part is a better value.

Aftermarket brands forum-validated for this vehicle:

• Bosch (This is the OEM supplier; the part is identical to the Genuine Mini part but costs less).

Brands owners have reported issues with on this vehicle:

• Unnamed, ultra-low-cost pumps from online marketplaces are not recommended due to the critical emissions function and the labor involved in replacement.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• 2733 — This is a manufacturer-specific (Mini) code for the DMTL pump system. TSB M01 05 11 specifically instructs dealers to replace the pump if this code is present, often alongside P1429.
• 2734 — A manufacturer-specific code that points to a fault within the DMTL pump module or its circuitry, providing a more precise diagnosis than the generic P1429.
• 2735 — Another specific Mini fault code related to the DMTL pump. Its presence strongly suggests the issue lies with the pump or its wiring, as outlined in Mini's service bulletin.
• 2736 — This is the last of the four key manufacturer-specific codes mentioned in TSB M01 05 11. If you see this code, the DMTL pump is the primary suspect.
• P2880 — While not related to the EVAP system, this code is very common on the N14 engine. It indicates a fuel pressure plausibility issue, typically caused by a failing High-Pressure Fuel Pump (HPFP), another known weak point on this vehicle.
• P0300 — This code for random/multiple cylinder misfires is often a symptom of severe intake valve carbon buildup, an inevitable issue on the N14's direct-injection engine that requires cleaning every 40,000-50,000 miles.
• P0012 — Indicates an over-retarded camshaft timing condition. On the N14 engine, this is a classic symptom of a failing timing chain tensioner, which can lead to the infamous 'Death Rattle' and catastrophic engine damage if ignored.

Frequently Asked Questions