Aston Martin V12 U1859 Engine Trouble Code
What is Aston Martin V12 U1859?
The Aston Martin V12 U1859 check-engine light can indicate issues ranging from minor (loose gas cap) to serious (catalytic converter failure). Professional diagnostic scanning at a dealer or shop will identify the exact cause and required repairs.
U1859 on the Aston Martin V12
On the Aston Martin V12, a secondary air injection pump that has seized due to moisture ingress is a common trigger for U1859. The fault is usually only present on cold starts and clears itself after two to three warm-up cycles, making it easy to overlook.
Code Information
| Code Type: | OBD-II Network (U) Trouble Code |
| System: | Network |
| Vehicle: | Aston Martin V12 |
| Brand: | Aston |
| Model: | Martin V12 |
| Code: | U1859 |
U1859 Aston Martin V12 Symptoms
Check Engine Light
Illuminated Aston Martin V12 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Aston Martin V12
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Aston Martin V12
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 V12 U1859
Diagnostic Steps:
Check if fuel pump primes when key is turned to ON. Measure fuel pressure and verify bright white-blue spark at all plugs. Also verify mechanical timing alignment.
Repair Solution:
VSS concerns may stem from noisy input signals caused by RFI/EMI from ignition wires, charging circuits, or aftermarket equipment. Verify VSS reads 0 mph when transmission is in Park.
Technical Notes:
U1859 DTC specifically relates to camshaft timing. When cam timing is over-retarded, the check-engine light illuminates and this code sets. Verify VCT solenoid operation and check for contamination.
Aston Martin V12 U1859 Repair Cost
Fuel injector cleaning service on the Aston Martin V12 costs $150–$300 for an ultrasonic bench-clean of all injectors with flow-test certification. On-car induction cleaning is a cheaper ($80–$120) first step but is less thorough for heavily fouled injectors.
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 V12
Replacing the PCM/ECU on the Aston Martin V12 for a persistent U1859 is a last-resort action that is often performed prematurely. Statistically, less than 2% of U1859 faults on this platform originate in the ECU; wiring, sensors, and mechanical causes account for the remainder.
DIY Repair Guide: U1859 on Aston Martin V12
Clearing U1859 on your Aston Martin V12 with a basic OBD-II reader ($20–$40) is straightforward: plug the reader into the diagnostic port under the dashboard, read the stored code, and clear it. If it returns within one drive cycle, the underlying fault is still present and requires attention.
Preventing U1859 on the Aston Martin V12
For Aston Martin V12 owners in high-humidity climates, applying electrical contact cleaner and dielectric grease to the ECU connector pins every two years prevents the corrosion-related signal errors that register as U1859.
Frequently Asked Questions — Aston Martin V12 U1859
A: It depends on the severity. If the check-engine light is steady, it is generally safe to drive to a workshop within the next few days. If the light is flashing, pull over safely as soon as possible — a flashing light indicates an active misfire that can cause expensive catalytic converter damage within minutes.