OBD-II Diagnostic Trouble Code
P0515 — Battery Temperature Sensor Circuit
P0515 indicates a fault in the battery temperature sensor circuit. The ECM uses this sensor to adjust charging voltage and found the signal out of its valid range or erratic. Not all trucks have this sensor; the meaning may vary by OEM.
Severity 2/5
Truck-relevant
Service soon
Severity
Service soon
Battery Temperature Sensor Circuit
Code
P0515
Category
Powertrain
Subsystem
Network
Truck-relevant
Yes
What this means for truckers
P0515 (Battery Temperature Sensor Circuit) — modern HD trucks have a battery temp sensor that informs alternator output. Fault can cause overcharging or undercharging in extreme temps. Sensor is usually in the battery box. Replacement: $80-200.
Before you replace parts — try this first
P0515 on the Network system is most often faulty battery temperature sensor — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Charging voltage may default to a fixed value, possibly overcharging in hot weather or undercharging in cold weather. Usually only a warning light is noticed; battery life may suffer over time.
Common causes
- CommonFaulty battery temperature sensor ($80–$250)
- CommonCorroded connector or damaged wire at the battery box ($80–$300)
- OccasionalSensor dislodged from its mounting ($30–$100)
- RareECM fault ($800–$2000)
How to fix
Inspect the sensor and wiring in the battery box for corrosion
When to use: First step
Compare sensor reading to actual ambient temperature on a cold soak
When to use: To check sensor accuracy
Replace the sensor
When to use: When readings are out of range with good wiring
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P0500 — Vehicle Speed Sensor Malfunction
- → P0501 — Vehicle Speed Sensor Range/Performance
- → P0502 — Vehicle Speed Sensor Low Input
- → P0503 — Vehicle Speed Sensor Intermittent/Erratic/High
- → P0506 — Idle Control System RPM Lower Than Expected
Frequently Asked Questions
Can I drive with code P0515?
P0515 is severity 2 — service this week. Not an immediate stop, but ignoring it usually compounds the problem. Most common cause for this code is a worn sensor or minor performance fault that won't strand you today but will get more expensive the longer you wait.
How much does it cost to fix P0515 on a commercial truck?
Total repair cost ranges $30–$2000 depending on the root cause. The cheapest fix is usually the first one listed below — Faulty battery temperature sensor — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P0515 fail a DOT inspection?
P0515 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between P0515 and related codes?
P0515 is closely related to: P0500 (Vehicle Speed Sensor Malfunction), P0501 (Vehicle Speed Sensor Range/Performance), P0502 (Vehicle Speed Sensor Low Input), P0503 (Vehicle Speed Sensor Intermittent/Erratic/High). These codes share the same subsystem (network) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P0515 is set without the companions, the issue is more isolated.
How do I prevent P0515 from coming back after a repair?
For P0515 (Battery Temperature Sensor Circuit), prevention centers on the network system. Pay attention to ground connections at every PM — bad grounds are 70% of communication codes. Inspect harness routing for chafe points. Don't disconnect modules with the key on.