ISO 9141-2:1994 PDF

Road vehicles — Diagnostic systems — Part 2: CARB requirements for interchange of digital information

Open preview (PDF)

Title (English):

ISO 9141-2:1994

Road vehicles — Diagnostic systems — Part 2: CARB requirements for interchange of digital information

Document status:: Active
Format:: Electronic (PDF)
Number of pages:: 14
Publication date:: February 3, 1994
Edition:: ISO IS 9141 edition 1 version 1
ICS:: 43.180

Delivery type:

Full version25 €Read online 24h10 €Read online 72h15 €

Document language:

enru

Delivery time:Immediate download

Price:25 €

Description (English):

Is limited to vehicles with nominal 12 V supply voltage. Describes a subset of ISO 9141:1989. Specifies the requirements for setting-up the interchange of digital information between on-board emission-related electronic control units of road vehicles and the SAE OBD II scan tool as specified in SAE J1978. This communication is established to facilitate compliance with California Code of Regulation, Title 13, 1968.1.

Technical details

Technical committee: ISO/TC 22/SC 31 - Data communication
SKU: ISO 9141-2:1994

Abstract

Overview

ISO 9141-2:1994 - "Road vehicles - Diagnostic systems - Part 2: CARB requirements for interchange of digital information" defines a CARB-focused subset of ISO 9141 for on‑board diagnostic communication between vehicle ECUs and an SAE OBD II scan tool. It is limited to nominal 12 V vehicle systems and was published to facilitate compliance with California Code of Regulation, Title 13, §1968.1 (malfunction and diagnostic systems requirements). The standard specifies initialization, header formats, signal levels, timing, and electrical limits needed for reliable exchange of emission‑related diagnostic data.

Key topics and technical requirements

Scope & compatibility
- Subset of ISO 9141:1989 targeted at OBD II communication with SAE J1978 scan tools.
- Connector compatibility per SAE J1962.
Physical lines
- Supports either one‑wire (K line) or two‑wire (K and L lines) configurations.
- K line: bidirectional after initialization; used for request/response messages.
- L line: unidirectional during initialization only; otherwise idles at logic “1”.
Initialization & header
- Diagnostic tester transmits a 5‑bit/s address (standard address 0x33) to invoke the protocol.
- Initialization includes speed synchronization, two key words, logic inversions for handshaking and configurable P2 response intervals.
Signal & timing
- Logic thresholds: transmitter logic “0” < 20% VB, logic “1” > 80% VB (receivers slightly different: 30%/70% VB).
- Bit coding: NRZ, slope time limits and sampling tolerances defined.
- Communication baud after init: 10.4 kbit/s ±1%.
- Key timing windows W0–W4 and P2 intervals specified (see Annex A in the standard).
Electrical limits
- Diagnostic tester cable capacitance CTE ≤ 2 nF; vehicle line capacitance Cosw ≤ 2 nF; total bus CEcu + Cobw

Related standards

Mentioned in the description and other ISO standards

Overview

Key topics and technical requirements

Scope & compatibility
- Subset of ISO 9141:1989 targeted at OBD II communication with SAE J1978 scan tools.
- Connector compatibility per SAE J1962.
Physical lines
- Supports either one‑wire (K line) or two‑wire (K and L lines) configurations.
- K line: bidirectional after initialization; used for request/response messages.
- L line: unidirectional during initialization only; otherwise idles at logic “1”.
Initialization & header
- Diagnostic tester transmits a 5‑bit/s address (standard address 0x33) to invoke the protocol.
- Initialization includes speed synchronization, two key words, logic inversions for handshaking and configurable P2 response intervals.
Signal & timing
- Logic thresholds: transmitter logic “0” < 20% VB, logic “1” > 80% VB (receivers slightly different: 30%/70% VB).
- Bit coding: NRZ, slope time limits and sampling tolerances defined.
- Communication baud after init: 10.4 kbit/s ±1%.
- Key timing windows W0–W4 and P2 intervals specified (see Annex A in the standard).
Electrical limits
- Diagnostic tester cable capacitance CTE ≤ 2 nF; vehicle line capacitance Cosw ≤ 2 nF; total bus CEcu + Cobw

ISO 9141-2:1994 PDF

Technical details

Abstract

Overview

Key topics and technical requirements

Related standards

Abstract

Overview

Key topics and technical requirements

Related standards

Road vehicles — Diagnostic systems — Requirements for interchange of digital information

Road vehicles — Diagnostic systems — Part 2: CARB requirements for interchange of digital information — Amend…

Systems and software engineering — Software life cycle processes

Asset management — Vocabulary, overview and principles

Asset management — Asset management system — Requirements

Information technology — Radio frequency identification device conformance test methods — Part 2: Test method…

Information technology — Multimedia framework (MPEG-21) — Part 22: User Description

Milk — Determination of the lactoperoxidase activity — Photometric method (Reference method)