What does P0374 mean?

Timing Reference High Resolution Signal 'A' No Pulses Engine may not start or may run poorly; rough idle, stalling or power loss possible

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Overview

Generic OBD-II code indicating the engine control module detects no high-resolution timing pulses from the 'A' timing reference sensor (often crankshaft or camshaft position signal), affecting ignition and fuel injection timing

Common Symptoms

Check Engine Light illuminated
Hard starting or no start condition
Rough idle or intermittent stalling
Reduced engine power

Most Common Causes

Faulty crankshaft position sensor or camshaft position sensor (designated as 'A' reference) high

No timing pulses detected by ECM often due to primary position sensor failure

Wiring harness issues (opens, shorts, corrosion) medium

Signal circuit disruption between sensor and ECM can stop pulses

Damaged or misaligned reluctor/tone wheel medium

Physical damage or missing teeth prevents pulse generation

Faulty ECM/PCM low

If sensors and wiring test good, module may not process signals correctly

Poor grounding or electrical interference low

Inadequate ground or noisy electrical environment can impede signal interpretation

Diagnostic Steps

Confirm P0374 with a scan tool and check for related codes

Expected: P0374 active and note any additional DTCs

Interpretation: Ensures accurate starting point and detects concurrent issues
Visual inspection of crankshaft/camshaft position sensor and wiring harness

Expected: No damaged wires or loose connectors

Interpretation: Physical faults likely cause signal loss
Test sensor output using multimeter or oscilloscope while cranking engine

Expected: Fluctuating voltage or pulses

Interpretation: Validates sensor is generating expected high-resolution signal
Inspect reluctor/tone wheel for integrity and alignment

Expected: Intact wheel with no missing teeth

Interpretation: Missing or misaligned tone wheel can prevent sensor pulses
Check circuit continuity and reference voltage from ECM

Expected: Continuity present and proper reference voltage (â‰ˆ5V)

Interpretation: Confirms sensor circuit and ECM reference are proper
If all above pass, test ECM input processing

Expected: ECM registers pulses when proper signal applied

Interpretation: Failure here suggests ECM internal fault

Repair Solutions

Replace faulty crankshaft or camshaft position sensor medium

Estimated Cost: $120 - $350

Cost depends on sensor type and vehicle application

Repair or replace damaged wiring/connectors medium

Estimated Cost: $50 - $200

May require wiring harness sections and connector kits

Replace or realign reluctor/tone wheel hard

Estimated Cost: $200 - $600

Labor can be significant if timing cover removal is needed

ECM reprogramming or replacement hard

Estimated Cost: $300 - $1200

Only after confirming no sensor/circuit faults remain

Common Misdiagnoses

Avoid these common diagnostic mistakes:

Fuel system or ignition misfire without verifying timing signal loss

Frequently Asked Questions

Technical definition of P0374 OBD-II Code

Technically, the P0374 code represents Timing Reference High Resolution Signal 'A' No Pulses. It usually points to a fault within the Sensors.

Should I stop driving if I have P0374?

With a severity level of high, engine may not start or may run poorly; rough idle, stalling or power loss possible

Common signs of the P0374 error code

The most typical signs are: Check Engine Light illuminated, Hard starting or no start condition, Rough idle or intermittent stalling.

Common triggers for the P0374 error

The most common causes are: Faulty crankshaft position sensor or camshaft position sensor (designated as 'A' reference), Wiring harness issues (opens, shorts, corrosion), Damaged or misaligned reluctor/tone wheel.

Estimated repair costs for different causes of P0374

It depends on what needs to be fixed. Repair or replace damaged wiring/connectors repairs are cheaper (~$200), while ECM reprogramming or replacement repairs are on the higher end (~$1200).

What cars are affected by the P0374 code?

The P0374 code is a generic powertrain code, meaning it applies to almost all makes and models, such as Honda, Toyota, VW, Ford, and Chevy.

P0374: Timing Reference High Resolution Signal 'A' No Pulses