P0073 low Severity

P0073: Ambient Air Temperature Sensor Circuit High

No significant impact on engine performance; may affect climate control and fuel trim in some vehicles

Overview

P0073 OBD‑II code: Ambient Air Temperature (AAT) Sensor Circuit High input — high voltage or implausible reading from ambient air temperature sensor circuit, frequently caused by wiring issues or failed sensor.

Common Symptoms

  • Check Engine Light (MIL) illuminated
  • Incorrect outside ambient temperature display
  • Climate control system malfunction or erratic behavior
  • Potential slight changes in fuel economy or idle behavior

Most Common Causes

Faulty ambient air temperature (AAT) sensor high

Sensor internal failure causing excessive voltage reporting beyond expected range

Damaged or corroded wiring/connectors to AAT sensor high

Corrosion, breaks, shorts, or poor connection leading to high circuit readings

Open circuit or short circuit in sensor wiring circuit medium

Wiring issues that cause incorrect high voltage signal to ECM

Faulty Engine Control Module (ECM) or climate/control module input low

Rare internal module failure misinterpreting signals

Diagnostic Steps

  1. Retrieve and confirm P0073 with OBD‑II scan tool
    Expected: Code P0073 present; observe live data for Ambient Air Temperature sensor reading
    Interpretation: Verifies correct trouble code and baseline data
  2. Visually inspect AAT sensor location, wiring harness, and connectors
    Expected: Check for physical damage, corrosion, loose or broken wires
    Interpretation: External evidence of damage can pinpoint wiring faults
  3. Test sensor reference voltage and output signal with multimeter
    Expected: Reference voltage (often ~5V) present; sensor output changes with temperature
    Interpretation: Proper voltage and logical output changes suggest sensor circuit integrity
  4. Measure sensor resistance/unplugged voltage compared to manufacturer specification
    Expected: Resistance or voltage should fall within expected range per temperature
    Interpretation: Out‑of‑range values indicate sensor failure
  5. Check continuity and short conditions to power or ground in wiring harness
    Expected: No unexpected continuity to 12V or ground outside specification
    Interpretation: Short or open circuits confirmed if readings deviate
  6. If sensor and wiring check OK, evaluate ECM input and software calibration
    Expected: ECM interprets injected known voltages correctly
    Interpretation: Failure at ECM input stage suggests module replacement/reprogramming

Repair Solutions

Replace ambient air temperature sensor easy
Estimated Cost: $20 - $150

Part is inexpensive; sensor usually located near front bumper/grille

Repair or replace damaged wiring/connectors medium
Estimated Cost: $50 - $300

Costs vary depending on harness routing and extent of damage

Reprogram or replace ECM if internal fault is confirmed hard
Estimated Cost: $600 - $1200

Only after all sensor and wiring tests confirm ECM issue

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Assuming climate control or HVAC actuator fault instead of sensor circuit issue

Frequently Asked Questions

What does the P0073 code mean?

When your OBD-II scanner reads P0073, it means: Ambient Air Temperature Sensor Circuit High. This code is related to the vehicle's Sensors.

Should I stop driving if I have P0073?

This is a low priority issue. No significant impact on engine performance; may affect climate control and fuel trim in some vehicles

Symptoms associated with DTC P0073

Common symptoms include: Check Engine Light (MIL) illuminated, Incorrect outside ambient temperature display, Climate control system malfunction or erratic behavior. You might also notice the Check Engine Light is on.

What causes the P0073 code?

The most common causes are: Faulty ambient air temperature (AAT) sensor, Damaged or corroded wiring/connectors to AAT sensor, Open circuit or short circuit in sensor wiring circuit.

What is the price difference for fixing P0073?

The cost varies significantly based on the root cause. For example, replacing a Replace ambient air temperature sensor typically costs between $20 and $150, while fixing a Reprogram or replace ECM if internal fault is confirmed can range from $600 to $1200.

What cars are affected by the P0073 code?

The P0073 code is a generic powertrain code, meaning it applies to almost all makes and models, such as Honda, Toyota, VW, Ford, and Chevy.

User Comments (0)

Share your experience or ask a question about this code.

Be the first to share your experience with P0073!