P1118 – Manifold Absolute Temperature Circuit Low Input: Symptoms, Causes, Diagnosis & Repair Cost (2026 Guide)

P1118

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Overview

The control module stored P1118 because it detected a problem with: Manifold Absolute Temperature Circuit Low Input.

P1118 relates to Manifold Absolute Temperature Circuit Low Input. Use a quality scan tool, follow wiring diagrams for your vehicle, and confirm tests before replacing expensive parts.

What does the P1118 code mean?

When P1118 is set, the vehicle’s diagnostics detected an issue described as: Manifold Absolute Temperature Circuit Low Input. In practice, the ECM/PCM (and related modules) compare sensor inputs, commanded outputs, and self-tests for that subsystem. The exact repair depends on whether the fault is wiring-related, component-related, or a rationality/performance issue for this circuit or system.

Common symptoms of P1118

  • Check engine light
  • Overheat in traffic
  • Reduced power if overheating
  • Temperature warning
  • Coolant smell or loss
  • Heater performance issues

Possible causes

  • Fault affecting Manifold Absolute Temperature Circuit Low Input (wiring, connector, or component)
  • Short-to-ground or bias low on the signal circuit
  • Reference voltage or ground issue
  • Damaged sensor or actuator internal fault
  • Control module or software calibration issue (less common—verify tests first)
  • Past repairs or aftermarket parts causing out-of-spec operation

How to diagnose P1118

  1. Scan for P1118 and review freeze frame / pending codes for related faults
  2. Inspect connectors and wiring related to: Manifold Absolute Temperature Circuit Low Input
  3. Compare live data and commanded vs actual values for the affected system (per service information)
  4. Perform circuit tests appropriate to the fault type (continuity, voltage, resistance) before replacing parts
  5. Confirm power and ground integrity at the relevant module or sensor
  6. After repair, clear DTCs and verify under the conditions that originally set P1118

Tip: Use a scan tool that shows live data and freeze frame for the conditions when the code set.

Severity of code P1118

Moderate: Have this code diagnosed soon; ignoring it can lead to worse fuel economy, repeat failures, or secondary damage.

Can you drive with P1118?

Short trips may be okay if the vehicle feels normal, but have it diagnosed—especially if performance, safety warnings, or overheating are present.

Avoid heavy acceleration, towing, or long highway drives until the cause of P1118 is confirmed and repaired.

How to fix it (step-by-step)

  1. Start with visual inspection and connector cleaning/tightening where needed
  2. Confirm failure mode with testing—avoid swapping parts without evidence
  3. Repair wiring or replace the failed component per manufacturer procedure
  4. Clear faults, run relearns if required, and road test to confirm

Repair & fix options

  • Locate and repair short-to-ground
  • Verify reference voltage and grounds
  • Replace failed sensor/actuator if confirmed
  • Clear codes and verify repair with a drive cycle and readiness where applicable
  • Reinspect related monitors if the code returns after repair

Typical repair cost

$120 – $3,000+ depending on cause

Estimated cost breakdown for P1118
Repair type Typical range
Diagnostic And Minor $120 – $550
Common Component Work $200 – $900
Major Subsystem Repair $200 – $800
Severe Or Replacement $800 – $3,000+

How to help prevent P1118 in the future

  • Fix new codes early before secondary damage or catalyst stress
  • Keep connectors clean and secure; address rodent or water intrusion in harnesses
  • Use the correct fluids/parts for your vehicle and service intervals
  • Avoid ignoring pending codes after battery work or repairs

When to see a mechanic

Schedule diagnosis if the check engine light is on, drivability is worse, or you notice new noises, smells, or warning lamps. For safety-related (SRS/ABS) or overheating symptoms, prioritize a qualified shop immediately.

Common mistakes when diagnosing P1118

  • Replacing sensors/modules without verifying wiring and reference voltages
  • Ignoring related codes that identify the real root cause
  • Clearing codes without a verification drive cycle

Common vehicles & notes for P1118

  • Ford / Chevrolet models (common examples—verify for your vehicle)
  • Toyota / Honda applications vary by engine and model year
  • Many other makes—this is a standardized OBD-II definition: Manifold Absolute Temperature Circuit Low Input

P1118 is reported across many platforms including Ford, Chevrolet, Toyota, Honda. Always use VIN-specific service information for testing limits and calibration steps.

Frequently asked questions

What does P1118 mean?

P1118 indicates a fault involving Manifold Absolute Temperature Circuit Low Input, based on what the control module detected during self-tests or live monitoring.

Is it safe to drive with P1118?

If the vehicle runs normally and no warning lights are flashing, short trips may be reasonable—but avoid ignoring symptoms like misfire, overheating, ABS/SRS warnings, or major loss of power.

How much does it cost to fix P1118?

Typical repairs often fall in the ranges shown on this page, but final cost depends on labor rate, parts quality, and whether the issue is wiring vs. a major component.

What is the most common cause of P1118?

Most shops start with wiring/connectors and the directly monitored component for “Manifold Absolute Temperature Circuit Low Input,” then expand testing if the fault returns.

Will P1118 clear itself?

It may become intermittent, but if the underlying fault remains, the code will usually return—especially after a drive cycle.

Can a weak battery cause P1118?

Low system voltage can cause odd sensor/module behavior, but you should still validate the actual DTC and perform normal circuit/component tests.

Related tools

This information is for educational purposes only and is not a substitute for hands-on diagnosis. Always follow manufacturer service information and consult a qualified automotive technician for repairs.