U0699 code meaning
Lost Communication With Coolant Pump F
Network system Generic code U06xx codes Check engine light
What U0699 means
Pump F is the sixth auxiliary electric coolant pump in the generic lettering, and the code flags that this pump has stopped responding on its data line. No manufacturer documents U0699 publicly; even the Mercedes bulletin that uses the E code for a low-temperature pump lists no F. Six separately addressed pumps point to elaborate thermal systems, for example vehicles with several cooling loops for engine, charge air, electronics and cabin. Such pumps typically take a PWM or LIN speed command and report their own condition, as Bosch describes for the PDE, and LIN is widely used for small motor nodes of this kind. CARB asks for an approved monitoring plan when an electric pump rather than a thermostat regulates engine temperature. P2D27 covers pump F's control performance.
U0699 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0699
- Warning light depending on manufacturer
- Loop served by pump F runs too warm
- Radiator fan running more often or at full speed
Common causes of U0699
- Most likelyData, supply or ground wire to pump F damaged
- PossiblePump F electronics or motor failed
- Less likelyControlling module or software fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Coolant pump fVehicle bus wiring
What each part of U0699 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 99 | The exact fault in that area. |
What to do next
- Note U0699 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0699
What does U0699 mean?
U0699 means "Lost Communication With Coolant Pump F". Pump F is the sixth auxiliary electric coolant pump in the generic lettering, and the code flags that this pump has stopped responding on its data line. It is a generic code, so it means the same on every make.
Is it safe to drive with U0699?
Drive gently and only to a workshop. With U0699 the car can go into limp mode (reduced power) to protect itself.
Will U0699 fail an emissions test?
Yes, it can. U0699 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U0699 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U0699 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.