2021-2024 Audi Coolant Pump Leak & DTC P0299 TSB

Owners of 2021-2024 Audi vehicles equipped with 2.9L or 3.0L V6 TFSI engines may encounter issues related to a mechanical coolant pump leak, leading to coolant loss, warning lights, and diagnostic trouble code P0299. This TSB, identified as 2070349/6, outlines the necessary steps for technicians to accurately diagnose and repair these conditions.

Symptoms

If your Audi is affected by this issue, you might notice one or more of the following symptoms:

• "Coolant loss/leak"
• "Coolant warning lamp" illuminated on the dashboard
• "Engine warning lamp on" illuminated on the dashboard

Fault Codes / DTCs

Technicians investigating an Audi coolant pump leak P0299 issue may find the following diagnostic trouble code (DTC) logged in the engine control unit:

• P0299: This code, often described as "P0299: Turbo/Super Charger Underboost," can be logged if the changeover valve N649 is compromised by coolant entry. This can lead to functional restrictions within the vehicle's vacuum system.

Important Warnings

Audi has issued a critical notice regarding the repair process for this TSB:

"Try to reproduce the customer complaint (based on the description/cause of the issue), so that it can be clearly assigned to this TSB. The following repair must only be carried out if all the criteria (model/type, chassis number, engine/motor, gearbox code, PR number(s), part number, software version, code, etc.) apply exactly. Otherwise, this solution will not eliminate the problem and repeat repairs may be necessary. In such a case, the warranty claim may be rejected, and the cost of the parts may be charged back."

This means that accurate diagnosis and strict adherence to the TSB's criteria are essential to ensure a successful repair and valid warranty claim.

Diagnosis and Trigger Conditions

To properly diagnose an Audi coolant pump leak P0299, technicians must precisely locate any leaks and ensure the coolant level drop is not due to insufficient bleeding from a previous repair. The TSB highlights that minor traces of coolant on the drip cup (as shown in Figure 1 of the bulletin) are considered a cosmetic leak for lubrication/cooling and do not warrant a repair. Similarly, dried deposits on vacuum connections (Figure 2) are not definitive proof of a leak.

Repair Procedure Summary

The repair procedure for the Audi coolant pump leak P0299 involves a systematic assessment and replacement of affected components. The steps are as follows:

1. Vacuum System Check: Inspect the vacuum line and changeover valve N649 (Checkpoint 1 in Figure 3) for any traces of coolant. If coolant is present, the mechanical coolant pump should be replaced, and further vacuum system checks performed.
2. Clean and Dry: Thoroughly clean and dry any suspected leak areas and coolant traces.
3. Cooling System Fill: Fill the cooling system to its maximum level.
4. Visual Leak Check: Perform a visual inspection for leaks at both idling speeds and higher engine speeds (around 2500 rpm).
5. Cooling System Leak Test: Conduct a comprehensive cooling system leak test using the workshop manual (ELSA).
6. Reassess Leak: Re-evaluate the suspected leak. If no leak is detected, further observation of the vehicle is recommended, and no parts replacement is necessary. If a leak is confirmed, the damaged component must be replaced, and the leak documented with photos or video. If the mechanical coolant pump is visibly leaking, its production date (Figure 4) should also be photographed.
7. Vacuum System Inspection (Continued): Systematically check checkpoints 2 and 3 (Figure 3) of the vacuum system for coolant residue. If fresh coolant is found, contaminated components such as vacuum line N545, coolant shut-off valve, and vacuum reservoir should be replaced. If no coolant residue is present, only valve N649 needs replacement, and the vacuum line between the coolant pump and N649 should be cleaned with compressed air.

Required Tools or Parts

Repairs may involve replacing various components, including:

• Mechanical coolant pump
• Regulating valve N649
• Regulating valve N545
• Vacuum pump
• Solenoid valve N75 with its entire vacuum line
• Vacuum reservoir (depending on specific model and contamination)

Technicians will use the Audi workshop manual (ELSA) for detailed procedures and specific part numbers. The TSB references Service Number 1950 and Damage Code 0050 for warranty claims related to this issue.

Owner Action

If you are experiencing symptoms of an Audi coolant pump leak P0299, such as coolant loss or warning lights, it is recommended to schedule an appointment with an authorized Audi service center. Provide them with a clear description of the symptoms you are observing. The diagnostic and repair procedures outlined in TSB 2070349/6 are intended for trained technicians to ensure proper resolution of the issue.

NHTSA ID: 11030999