P1429 on 2007-2013 Mini Cooper: DMTL Heater Circuit Fault Causes and Fixes

What's Unique About the 2007-2013 Mini Cooper

The second-generation Mini Cooper (R56) uses a sophisticated Bosch DMTL pump to check for fuel vapor leaks. Failures in this system are common enough that Mini issued a warranty extension for the pump on these models, including those with the N12 engine (TSB M01 05 11). Owner and technician experiences show that the wiring leading to the pump is particularly vulnerable to damage from road debris and weather, often being the true cause of the fault rather than the pump itself. A notable design flaw involves the wiring harness being improperly secured to the rear suspension swing arm, causing wires to fray and break from repeated movement.

Symptoms You May Notice

• Check Engine Light is on
• No noticeable drivability issues
• Inability to pass a state emissions inspection

Most Likely Causes

1. Damaged or Corroded Wiring Harness 🔴 High Probability The DMTL pump and its wiring are located behind the rear passenger-side wheel well liner, exposing them to moisture, road salt, and debris. A specific design flaw has been noted where the harness is attached to the moving rear swing arm, causing constant flexing that eventually breaks the wires internally. This can cause an open circuit for the heater, solenoid, and pump motor, often simultaneously.
   How to confirm: Visually inspect the wiring harness leading to the DMTL pump connector. Pay close attention to the section of the harness that is routed near the rear passenger-side suspension swing arm; check for chafing, breaks, or signs of a previous repair. Test for 12V power at the Red/White wire on the 3-pin connector with the ignition on. If power is absent, the wiring is faulty. Gently tug on each wire at the connector to ensure it's secure.
   Typical fix: Repair the damaged section of the wiring harness using solder and heat-shrink tubing for a durable fix. If the break is due to the swing arm flaw, re-route the repaired harness so it is secured to the body or charcoal canister bracket, not the moving suspension component. Protect the repaired area with new conduit or high-quality electrical tape. If the connector itself is corroded, it may need to be replaced. A connector repair kit (pigtail) may be available from the dealer or aftermarket suppliers. BMW/MINI part number 61132359998 is a common 3-pin repair connector kit that may fit.
   Est. part cost: $5-$40 for wiring repair supplies or a new connector pigtail
2. Failed DMTL Pump 🟡 Medium Probability The internal heater element within the pump can burn out, creating an open circuit. The pump itself was subject to a warranty extension (TSB M01 05 11), indicating a known higher-than-average failure rate for the component due to defects in materials or workmanship.
   How to confirm: After confirming the wiring is intact and has power (approx. 12V) and ground at the connector, the pump is the remaining point of failure. You can test the heater circuit's resistance directly at the pump's pins with a multimeter. Disconnect the pump and measure between the relevant pins; an infinite resistance reading (OL) indicates an open circuit and a failed heater. While a specific resistance value is not commonly published, a reading of OL confirms internal failure.
   Typical fix: Replace the DMTL pump. The pump is mounted on the charcoal canister with three small Torx screws.
   Est. part cost: $70-$150

Rare But Worth Checking

• Failed Engine Control Module (DME):

Diagnosis Steps

1. Retrieve the P1429 code using an OBD-II scanner.
2. Safely lift and support the rear of the vehicle. Remove the passenger-side rear wheel.
3. Remove the plastic wheel well liner to gain access to the charcoal canister and the attached DMTL pump. This is typically held in by several plastic rivets and small bolts.
4. Carefully inspect the wiring harness and 3-pin connector going to the DMTL pump. Pay special attention to the harness routing near the rear suspension swing arm for signs of chafing or broken wires from repeated flexing.
5. If wiring damage is found, repair the affected wires. Ensure the repaired harness is routed away from moving suspension parts. Clear the codes and drive the vehicle to see if the code returns.
6. If the wiring appears to be in good condition, disconnect the pump. Use a multimeter to check for power (approx. 12V) on the Red/White wire and for a good ground at the connector with the ignition on. A wiring diagram is recommended for the correct pinout.
7. If power and ground are present, the DMTL pump has likely failed internally. Test the resistance of the heater circuit pins on the DMTL pump itself. An out-of-spec or infinite resistance reading (OL) confirms the pump has failed internally.
8. If the pump has failed, replace the DMTL pump. It is held to the charcoal canister with three Phillips or Torx head screws. Be careful not to damage the charcoal canister during removal.
9. Ensure the new pump comes with a new sealing O-ring and that it is properly seated during installation.
10. After replacement, clear the codes. Perform a drive cycle or use a capable scan tool to run the EVAP system self-test to confirm the fix.

Parts You'll Likely Need

• Diagnostic Module Tank Leakage (DMTL) Pump (OEM #16137193479) — This part contains the heater element that fails and triggers the P1429 code. It's the component to replace if the wiring is confirmed to be good. The part was updated to an 'improved version' according to Mini's TSB.
  Trusted brands: Bosch (OEM), URO Parts, Standard Motor Products
  OEM price range: $120-$180
  Aftermarket price range: $70-$110
• DMTL Pump Connector Repair Kit (OEM #61132359998) — If the connector housing or pins are damaged by corrosion, this pigtail allows for a clean replacement without replacing a larger section of the harness.
  Trusted brands: BMW/MINI (Genuine)
  OEM price range: $25-$40
  Aftermarket price range: $15-$25

Related Codes That Often Appear With This One

• P1447 — This code indicates the DMTL pump current is too high during the diagnostic, which can be related to other electrical failures within the same component.
• P1449 — Similar to P1447, this code also points to excessive current draw in the DMTL pump, suggesting an internal electrical short rather than an open circuit.
• 2733, 2734, 2735, 2736 — These are manufacturer-specific fault codes for 'DMTL, module error' that may be present alongside the generic P1429 code when read with more advanced scan tools. TSB M01 05 11 specifically mentions these codes as triggers for replacing the pump under warranty.
• 271B, 272A, 272E — These are BMW/Mini specific codes for 'DMTL heater', 'DMTL solenoid valve', and 'DMTL pump motor' respectively. Seeing them together strongly points to a wiring harness issue affecting the shared power or ground to the pump assembly.

Technical Service Bulletins (TSBs) & Recalls

• M01 05 11 - Extended warranty coverage for the Fuel Tank Leak Diagnostic Module (DMTL) pump to 10 years/120,000 miles. It applies to 2007-2009 R56 Cooper models, among others, with the N12 engine. The TSB instructs dealers to replace the pump if specific DMTL-related faults (like 2733, 2734, etc.) are present, without performing further test plans.

Platform-Specific Known Issues

• Mini extended the limited warranty for the DMTL pump to 10 years or 120,000 miles for many R56 models due to a high failure rate. Check with a dealer to see if your vehicle is still covered, though most 2007-2013 models will now be outside this window.
• Owners on forums like North American Motoring frequently report that the nuts holding the charcoal canister bracket can rust and spin in place, making removal difficult. Applying penetrating oil beforehand and potentially using a second tool to hold the stud from the back may be necessary.
• A significant design flaw exists where the wiring harness for the DMTL pump is routed from the car's body to the moving rear suspension swing arm and back to the body. This creates a 'sawing' motion that fatigues and breaks the wires over time, causing open circuit faults like P1429.

Mechanic-Grade Diagnostic Values

• Voltage at DMTL Pump Connector — expected: Approx. 12V (Battery Voltage). Failure: 0V or significantly low voltage indicates a wiring or fuse issue upstream of the connector.
• DMTL Pump Heater Circuit Resistance — expected: A specific Ohm value is not commonly cited in field repairs.. Failure: An infinite resistance (OL) reading across the heater pins on the pump confirms an internal open circuit, necessitating pump replacement.

Hidden / Shadow Codes Worth Checking

• 271B: DMTL Heater Circuit (see via BMW/MINI specific scan tool like Foxwell, Autologic, or ISTA.)
• 272A: DMTL Solenoid Valve (see via BMW/MINI specific scan tool like Foxwell, Autologic, or ISTA.)
• 272E: DMTL Pump Motor (see via BMW/MINI specific scan tool like Foxwell, Autologic, or ISTA.)
• 2733, 2734, 2735, 2736: DMTL, module error (see via BMW/MINI specific scan tool. These codes are specifically cited in TSB M01 05 11 as a trigger for warranty replacement.)

Scan Tool Commands That Help

• ISTA (BMW/MINI Dealer Software): DMTL pump activation / Fuel tank leakage diagnostic module test — Use this after a repair to run a complete system self-test and confirm the fix without waiting for a natural drive cycle. It pressurizes the system and checks pump function, providing a pass/fail result.
• Autologic AssistPlus (or similar advanced aftermarket scanner): Service Functions > DME > Diagnose module for tank leaks — This forces the DMTL monitor to run, which includes a reference leak, minor leak, and micro leak test, taking up to 10 minutes. It's used to verify a repair was successful and to get the EVAP readiness monitor to show 'Complete' for an emissions inspection.

Wiring & Ground Locations

• DMTL Pump Connector Power Wire — On the 3-pin connector at the DMTL pump, behind the passenger-side rear wheel well liner.. This wire, typically Red with a White stripe, should have ~12V with the key on. No voltage here points to a broken wire, blown fuse, or DME fault, not a failed pump.
• DMTL Harness Chafe Point — The section of the wiring harness that is routed near or attached to the rear passenger-side suspension swing arm.. This is a known failure point. The harness is secured to the body, then the moving swing arm, then the body again. This creates a pivot point where repeated suspension travel can fatigue and break the wires, causing an open circuit for the DMTL pump heater and motor.
• Rear Ground Point — There is a common ground plate on the right side of the rear chassis, near the curve for the wheel well.. A loose or corroded ground connection at this point could cause intermittent or permanent faults for components in the rear of the vehicle, including the DMTL pump.

Real Owner Repair Stories

• YouTube channel 'CoolAirVw Rm' (2010 Mini Cooper (R56)) — Check Engine Light with multiple EVAP open circuit codes (P2418, P2400) and manufacturer codes 271B (DMTL heater), 272A (solenoid), 272E (pump motor).
  ❌ Tried (didn't work) Initial check of the fuse in the fuse box, which was found to be good.
  ✅ What actually fixed it The technician discovered that the wiring harness for the DMTL pump was improperly routed and attached to the moving rear suspension swing arm. The constant flexing had frayed and broken the wires. The final fix was to repair the broken wires with solder and heat shrink, and then re-route the harness so it was secured to the stationary charcoal canister bracket, preventing future damage.

OEM Part Supersession History

• 16136752551, 16136764191, 16130428344 → 16137193479 — This part has been redesigned and superseded multiple times. The latest part number is referred to as an 'improved version' in service bulletins.

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 Stretch & Guide Failure 🔴 High — Very common, especially on pre-2011 models. Often presents as a 'death rattle' noise on cold starts. Can occur as early as 50,000-60,000 miles. (Ref: Multiple TSBs exist, including SIM-11-05-12 which addresses a leaking tensioner seal.)
• Thermostat Housing & Water Pump Leaks 🔴 High — Extremely common. The plastic thermostat housing is prone to cracking and leaking due to heat cycles. The water pump can also leak. Failure can lead to rapid coolant loss and overheating.
• VANOS Solenoid Failure 🟠 Medium — Common issue, often caused by oil sludge or low oil levels. Leads to rough idle, poor performance, and VANOS-related fault codes. Relatively easy to clean or replace.
• Excessive Oil Consumption 🟠 Medium — Common, often due to failing valve stem seals. Can lead to blue smoke from the exhaust and requires frequent oil top-ups. (Ref: SI M01 05 15 addresses procedures for oil top-ups under the maintenance program.)
• Leaking Vacuum Pump 🟠 Medium — The seal on the engine-driven vacuum pump often fails, causing an oil leak down the back of the engine. In worst cases, the pump can seize and damage the camshaft.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: Given the known high failure rate of the original DMTL pump, which prompted a warranty extension, buying a used part is generally not recommended. A used part is only a viable option if you can verify it is the updated part number (16137193479) and it comes from a very low-mileage, late-model donor vehicle that was not in a rear-end collision.

Donor-vehicle mileage cap: roughly under 40000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• Ensure the part number is the updated Bosch version: 16137193479.
• Inspect the plastic housing for any cracks or signs of heat stress.
• Check the electrical connector pins for any corrosion or damage.
• Ask for the donor vehicle's VIN to check its age and mileage if possible.

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

• DMTL Pump

Aftermarket brands forum-validated for this vehicle:

• Bosch (This is the Original Equipment Manufacturer, OEM)

Brands owners have reported issues with on this vehicle:

• Unbranded, no-name pumps from online marketplaces are a significant gamble. Given the relatively low cost of the OEM Bosch part, it is the recommended choice to avoid repeat repairs.

Real Owner Stories

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

Frequently Asked Questions