User's Guide

Defaults and customization
By default, the following mapping of PID value to OVMSv3 metric is used:
PID
Requested
Parameter
Mapped
Metric value
Metric
Name
Dec
Hex
4
0x04
Engine Load
Battery SOC
v.b.soc
5
0x05
Coolant Temp
Motor Temp
v.m.temp
12
0x0c
Motor RPM
Motor RPM
v.m.rpm
13
0x0d
Vehicle Speed
Vehicle Speed
v.p.speed
16
0x10
MAF Air Flow
12v Battery
v.b.12v.voltage
The OBDII ECU task supports the remapping and reporting of PIDs 4-18, 31, 33, 47, and 51 (all
decimal). PIDs #0 and 32 are used by the OBDII protocol for management, and not available
for assignment. Other PIDs return zero.
PIDs requested for which no mapping has been established are ignored by the OBDII ECU task.
As an aid for discovering which PIDs are being requested, the configuration parameter
'autocreate' may be used to populate entries into the obdii ecu list display. ('config set obd2ecu
autocreate yes'). Such autocreated entries are marked as "Unimplemented", and return zero to
the device. They are not added to the configured (saved) obd2ecu.map, and get cleared at
each boot or reset. They may be mapped to a supported metric, if desired, using:
config set obd2ecu.map <PID> <metric name>
Example:
OVMS# config set obd2ecu.map 5 v.b.temp
(map battery temp to engine coolant temp)
OVMS# vfs edit /store/obd2ecu/10
(script for fuel pressure PID; see below)
OVMS# obdii ecu reload
OBDII ECU pid map reloaded
OVMS# obdii ecu list
OVMS v3 User Guide Page 75 / 86