Aston Martin Db5 U1859 Engine Trouble Code
What is Aston Martin Db5 U1859?
With Aston Martin Db5 U1859, you may drive for several weeks with a malfunctioning MAF sensor, but expect decreased fuel economy and eventual stalling. Shop replacement costs $240–$400 depending on vehicle. The labour is straightforward, with most cost from the part itself.
U1859 on the Aston Martin Db5
Owners of the Aston Martin Db5 should be aware that U1859 can appear alongside oil consumption warnings. Low oil pressure caused by a worn PCV system lets crankcase vapour contaminate the mass air flow sensor, sending erroneous readings to the ECU.
Code Information
| Code Type: | OBD-II Network (U) Trouble Code |
| System: | Network |
| Vehicle: | Aston Martin Db5 |
| Brand: | Aston |
| Model: | Martin Db5 |
| Code: | U1859 |
U1859 Aston Martin Db5 Symptoms
Check Engine Light
Illuminated Aston Martin Db5 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Aston Martin Db5
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Aston Martin Db5
Increased Emissions
Failed emissions test due to U1859
U1859 Code Structure
Understanding what each digit means in the U1859 network trouble code:
| U | 1 | 8 | 5 | 9 |
|---|---|---|---|---|
| Network Code | Fuel And Air Metering | Engine Oil Temperature Sensor Malfunction | Cylinder 1 Injector Circuit Low | Reverse Input Circuit |
How to Fix Aston Martin Db5 U1859
Diagnostic Steps:
Poor running symptoms align with MAP sensor malfunction. In some cases, a faulty MAP sensor will not trigger a code. The issue may represent separate wiring concerns requiring individual diagnosis.
Repair Solution:
Excessive air inflow may result from vacuum leaks, dirty sensors, or EGR valves not closing properly. Insufficient fuel can stem from dirty injectors, clogged filters, weak fuel pump, or leaking pressure regulator.
Technical Notes:
U1859 DTCs can be triggered by upstream issues. For example, a dirty MAF sensor may cause incorrect fuel-trim adjustments, leading oxygen sensors to report mixture problems. Address root causes first.
Aston Martin Db5 U1859 Repair Cost
For Aston Martin Db5 owners, budget the following for a U1859 repair: EGR valve cleaning $80–$120 or replacement $250–$450, intake manifold gasket $120–$200, and a post-repair reset and road test. Total: $350–$650 at an independent garage.
U1859 Description
U1859 engine trouble code is related to Reverse Input Circuit.
Main Cause
The primary reason for U1859 OBD-II Engine Trouble Code is: Engine Oil Temperature Sensor Malfunction.
Common U1859 Misdiagnosis on the Aston Martin Db5
Many Aston Martin Db5 owners have unnecessarily replaced the MAF sensor for U1859. In 60% of confirmed cases, the sensor was simply contaminated and required a $10 aerosol clean rather than a $200 replacement.
DIY Repair Guide: U1859 on Aston Martin Db5
Replacing the spark plugs on the Aston Martin Db5 is rated a difficulty 2/5 for home mechanics. The top-mounted plug access on this engine requires a 3/8" extension and a 14mm spark plug socket. Always torque to the manufacturer's specification to avoid cracking the cylinder head.
Preventing U1859 on the Aston Martin Db5
Transmission fluid degradation on the Aston Martin Db5 directly affects solenoid operation. Replacing ATF at 40,000-mile intervals (rather than the often-quoted 'lifetime fill' recommendation) is the best insurance against shift-solenoid codes including U1859.
Frequently Asked Questions — Aston Martin Db5 U1859
A: Clearing the code without repair allows the fault condition to persist. Depending on the cause, this can lead to catalytic converter damage, increased fuel consumption, and secondary component failures that are significantly more expensive to address than the original fault.