📍 680 Lake St · Roselle, IL 60172 Mon–Fri 8a–6p · Sat 8a–3:30p · Sun 9a–12p (630) 894-7077
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Engine diagnostics
decoded.

Check engine light on? Drivability acting weird? We pull the codes with manufacturer-specific scanners, find the actual root cause, and explain it in plain English — no jargon, no scare tactics.

ALL MAKES · DOMESTIC, FOREIGN, HYBRID, EVWRITTEN QUOTE BEFORE ANY WORK
ASE-certified technician running engine diagnostics on a customer car at Allied Auto Services in Roselle
SYMPTOMS WE SEE

When to bring it in.

SYMPTOM · 01

Check engine light

Solid or flashing — both deserve attention. We pull the actual codes plus live data, not just a generic OBD-II reader.

SYMPTOM · 02

Hard start / no start

Cold start, hot start, intermittent? Could be ignition, fuel, sensor, or battery. We find which.

SYMPTOM · 03

Stalling or misfiring

Hesitation under load, rough idle, or random misfires — we test under real driving conditions.

SYMPTOM · 04

Loss of power

Reduced engine power warning, limp mode, or noticeable sluggishness. Often a turbo, sensor, or fuel issue.

Inside the Allied Auto Services bay during a diagnostic
WHAT WE DO

Diagnostic services we offer

Engine bay diagnostic with manufacturer-specific scanner

Computer / ECU diagnostics

Full code scan + live data analysis. Manufacturer-specific tooling for European, Asian, and domestic vehicles.

Quote on inspection

Drivability diagnostics

Stalling, hesitation, misfires, lack of power — diagnosed under real load conditions.

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Pre-purchase inspection

Buying used? We’ll go top-to-bottom and tell you what you’re really getting. Photos and video included.

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Electrical & ignition

Battery, alternator, starter, ignition coils, sensor and wiring diagnosis.

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READY WHEN YOU ARE

Pick up the
phone.

Call Now · (630) 894-7077