Engine Controls - Self-Diagnostics - Introduction: Diagnosis Suzuki Esteem I

DIAGNOSTIC TROUBLE CODES (DTC)

Powertrain Control Module (PCM) is equipped with a self-diagnostic system, which detects system failures or abnormalities. When a malfunction occurs, PCM will illuminate Malfunction Indicator Light (MIL) located on instrument cluster. If operation of MIL is in question, see MALFUNCTION INDICATOR LIGHT (MIL) CHECK .

When a malfunction is detected and MIL is illuminated, a corresponding DTC will be stored in PCM memory. Each DTC is directly related to a specific diagnostic test. See appropriate SELF-DIAGNOSTICS article.

PRELIMINARY DIAGNOSTIC PROCEDURE

Note. The following diagnostic procedure requires use of a scan tool. See SPECIAL TOOLS (DIAGNOSTIC) .

Diagnosis of computerized engine control system should be performed in the following order

1. Verify customer complaint. Using scan tool, obtain and record DTC and freeze frame data. Erase DTCs if present. See «MALFUNCTION INDICATOR LIGHT (MIL) RESET PROCEDURE»(ref-91182-S41574356062001030500000) . Perform a visual inspection and ensure all engine systems not related to computer are operating properly. DO NOT proceed with diagnosis unless all other problems have been repaired.
2. Using scan tool, attempt to retrieve DTCs once more. If DTC(s) are present, perform appropriate diagnostic test. See DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article. If DTC(s) are not present, and a driveability problem or intermittent problem is present, go to «TROUBLE SHOOTING - NO CODES»(ref-91186) article.

Note. ALWAYS erase DTCs, confirm closed loop operation, and test drive vehicle after repairs are completed. Ensure MIL DOES NOT illuminate.

SPECIAL TOOLS (DIAGNOSTIC)

Note. Scan tools save a great deal of diagnostic time and help prevent replacement of good parts. Most procedures and diagnostic tests related to computerized engine control system are intended to be used in conjunction with a scan tool. Any computer related diagnosis without a scan tool is NOT recommended.

The computerized engine control system is diagnosed using a Tech 1 or other OBD-II compatible scan tool. However, other tools are needed to aid in diagnosing problems. These tools include a tachometer (inductive pick-up), a non-powered test light, Digital Volt-Ohmmeter (DVOM) with 10-megohm input impedance (minimum), vacuum pump and vacuum gauge, High Energy Ignition (HEI) spark tester, fuel pressure gauge, fuel injector test light (noid-light), and fused jumper wires. A test light, rather than a voltmeter, must be used when indicated by a diagnostic test procedure.

SCAN TOOL USAGE

Note. Before connecting scan tool, follow steps in MALFUNCTION INDICATOR LIGHT (MIL) CHECK .

Scan tool is a specialized tester which can diagnose on-board computer control systems by providing almost instant access to circuit data without crawling under instrument panel or engine hood to backprobe sensors and connectors. Scan tools reduce diagnostic time by furnishing input data (sensor values) which can be compared to specification parameters.

Scan tools also furnish status data of output devices (solenoids and motors). However, status parameters are only an indication that output signals have been sent to devices by PCM. They do not indicate if devices respond properly to that signal. This must be verified at output device using a DVOM or test light.

If DTCs are not present, a problem may still exist. Driveability-related problems with DTCs displayed occur about 20 percent of the time, while driveability problems without DTCs occur about 80 percent of the time. Out-of-calibration sensors may NOT set a DTC, but WILL cause driveability problems. A scan tool is the easiest method of checking sensor specifications and other data parameters. A scan tool is also useful in finding intermittent wiring problems by wiggling wiring harnesses and connections (key on, engine off) while observing data parameters.

Note. Information obtained by a scan tool is only as accurate as the scan tool itself. A scan tool that displays faulty data should not be used. If faulty data readings are suspected, verify scan tool information using a DVOM and wiring schematic.

DTC DEFINITION

DTC IDENTIFICATION (ESTEEM & SWIFT)

DTC IDENTIFICATION (GRAND VITARA & VITARA)