Data Output with a Scan Tool

The output of data relevant to OBD from the control modules was stipulated by law for the USA. It is described in SAE J 1979.

Data output is subdivided into different modes.

Mode 1

Output of:

Input signals
Output signals
System status information
Values calculated by the control module

Mode 2

Output of operating conditions (freeze frame) when a fault is stored in the memory (also see DME control module signal output ).

Mode 3

Output of stored faults.

Mode 4

Erase the fault memory.

Mode 5

Output of oxygen sensor data.

Mode 6

Output of test results of non-continuous tests.

Mode 7

Output of test results of continuous tests. (Output of suspected faults)

The data sets in the modes are referred to as Parameter Identification (PID).

After being stimulated by a generic scan tool, all systems relevant to OBD log on with their address. In vehicles with ME 7.2 this is the DME with the address $]] and in Tiptronic vehicles it is the transmission control module with the address $]A.

NOTE: The $ symbol means that a hexadecimal number is involved.

When the control module provides data, it also states the mode, the PID number and the address of the control module.

Example

Mode 41Pid$01 Adr$11

Engine control

No. of faults: 0

MIL commanded OFF

Data output takes place

with Mode 41 in Mode 1,

with Mode 42 in Mode 2,

with Mode 43 in Mode 3 etc.

Mode 1

The following PIDs are supported in Mode 1:

$00 Supported PIDs

The PIDs supported in this mode are displayed in a 4-byte word (Data A, B, C and D).

Data A

PID 01 to 08

Fig 1: Identifying Data A PID 01-08

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Data B

PID 09 to 10

Fig 2: Identifying Data B PID 09-10

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Data C

PID 11 to 18

Fig 3: Identifying Data C PID 11-18

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Data D

PID 19 to 20

Fig 4: Identifying Data D PID 19-20

Courtesy of PORSCHE OF NORTH AMERICA, INC.

0 - PID number not supported.

1 - PID number supported.

$01 Status of diagnostic system

The system status is displayed in a 4-byte word (Data A, B, C and D).

Data

A: 1000 0001
B: 0000 0111
C: 0110 1101
D: 0110 1101

Data A

Fig 5: Identifying Data A Binary

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Bits 0 to 6

No. of faults in binary format

Bit 7

0 - Check Engine MIL was not switched on by this control module.

1 - Check Engine MIL was switched on by this control module.

Data B

Fig 6: Identifying Data B Binary

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Data byte B displays all the sub-systems which are monitored continuously, i.e. at least twice per second.

Bit 0 - Misfire detection

Bit 1 - Fuel system

Bit 2 - Other components

Bit 3 - Not used

Bit 4 - Not used

Bit 5 - Not used

Bit 6 - Not used

Bit 7 - Not used

0 - System not supported.

1 - System supported.

Data C

Fig 7: Identifying Data C Binary

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Data byte C displays the sub-systems which are monitored at least once per driving cycle.

Bit 0 - TWC

Bit 1 - TWC heating

Bit 2 - Fuel tank ventilation

Bit 3 - Secondary air system

Bit 4 - A/C system

Bit 5 - Oxygen sensor

Bit 6 - Oxygen sensor heating

Bit 7 - Exhaust gas circulation

0 - Sub-system not available.

1 - Sub-system available.

Data D

Fig 8: Identifying Data D Binary

Courtesy of PORSCHE OF NORTH AMERICA, INC.

In data byte D, the readiness codes of the sub-systems from data byte C are displayed.

Bits 0 to 7

0 - Sub-system check completed or sub-system not installed.

1 - Sub-system check not yet complete.

NOTE: After the fault memory has been erased, the bits of the installed sub-systems where a fault was present are set to 1.

The bits are reset to 0:

after 1 driving cycle if the check was fault-free
after 2 driving cycles if a fault was detected.

$03 Status of injection system

Data

A: 0000 0010
B: 0000 0010

Data A - Status of bank 1

Data B - Status of bank 2

Fig 9: Identifying $03 Status Of Injection System Binary

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Bit 0 - Open-loop control, the conditions for closed loop oxygen sensing have not yet been satisfied.

Bit 1 - Closed-loop control, the signal from the oxygen sensor is used to control injection.

Bit 2 - Open-loop control through conditions such as full load, etc.

Bit 3 - Open-loop control through faults in the system.

Bit 4 - Closed-loop control, but faults from at least one oxygen sensor.

Bits 5 to 7 not used.

NOTE: Only one bit at a time can be set to 1 to indicate the status.

$04 Calculated load value

Output of calculated load as a percentage of the maximum load.

Display between 0% and 100%.

$05 Engine coolant temperature

Output of the momentary engine coolant temperature. Display between - 40° C and 215° C.

$06 HO2S integrator, bank 1

Output of the control value FR of the oxygen sensor closed-loop control, bank 1.

Display: lean to - 100%

rich to 99.22%

$07 HO2S adaptation, bank 1

Output of the adaptation value FRA of the oxygen sensor closed-loop control, bank 1.

Display: lean to - 100%

rich to 99.22%

$07 HO2S integrator, bank 2

Output of the control value FR of the oxygen sensor closed-loop control, bank 2.

Display: lean to - 100%

rich to 99.22%

$09 HO2S adaptation, bank 2

Output of the adaptation value FRA of the oxygen sensor closed-loop control, bank 2.

Display: lean to - 100%

rich to 99.22%

$OC Engine speed

Output of the momentary engine speed.

Display of engine speed in rpm.

$OD Vehicle speed

Output of the speed currently travelled.

Display of speed in ^km/h up to a maximum of 255 ^km/h

$OE Ignition timing, cylinder 1

Output of the ignition angle from cylinder 1.

Display: after TDC up to - 64 °crk

before TDC up to 63.5 °crk

°crk - degrees crank angle

$OF Intake air temperature

Output of intake air temperature.

Display between - 40° C and 215° C.

$10 Air mass

Output of the intake air mass. Display between 0 and 655.35 g/s g/s - Grams per second

$11 Throttle valve position

Output of the absolute throttle angle.

Display between 0% and 100%

$12 Status of secondary air system

Data A

Fig 10: Identifying $12 Status Of Secondary Air System (Data A)

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Bit 0 - secondary air is injected before the catalytic converter.

Bit 1 - not used.

Bit 2 - secondary air pump is switched off.

Bits 3 to 7 not used.

NOTE: Only one bit at a time can be set to 1 to indicate the status.

$13 Number of oxygen sensors

Output of the number and location of oxygen sensors.

Fig 11: Identifying $13 Number Of Oxygen Sensors Binary

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Bit 0 - bank 1, sensor 1 (ahead of catalytic converter, cylinders 1-3)

Bit 1 - bank 2, sensor 1 (after catalytic converter, cylinders 1-3)

Bit 2 - bank 1, sensor 3 not installed

Bit 3 - bank 1, sensor 4 not installed

Bit 4 - bank 2, sensor 4 (ahead of catalytic converter, cylinders 1-6)

Bit 5 - bank 2, sensor 2 (after catalytic converter, cylinders 4-6)

Bit 6 - bank 2, sensor 3 not installed

Bit 7 - bank 2, sensor 4 not installed

0 - sensor not present

1 - sensor present

$14 Oxygen sensor signal, bank 1, sensor 1

Display of oxygen sensor voltage and associated oxygen sensor.

Display of sensor voltage between 0 V and 1.275 V and of the oxygen sensor in percent.

Display: lean to - 100%

rich to 99.22%

$15 Oxygen sensor signal, bank 1, sensor 2

Display of oxygen sensor voltage and associated oxygen sensor.

Display of sensor voltage between 0 V and 1.275 V and of the oxygen sensor in percent.

Display: 99.22%

NOTE: Since the sensor behind the catalytic converter is not included in the closed- loop control, 99.22% is displayed.

$18 Oxygen sensor signal, bank 2, sensor 1

Display of oxygen sensor voltage and associated oxygen sensor.

Display of sensor voltage between 0 V and 1.275 V and of the oxygen sensor in percent.

Display: lean to - 100%

rich to 99.22%

$19 Oxygen sensor signal, bank 2, sensor 2

Display of oxygen sensor voltage and associated oxygen sensor.

Display of sensor voltage between 0 V and 1.275 V and of the oxygen sensor in percent.

Display: 99.22%

NOTE: Since the sensor behind the catalytic converter is not included in the closed- loop control, 99.22% is displayed.

$1C OBD requirements

Display of system classification.

01 - OBD II for California

02 - OBD for EPA

03 - OBD II for California and EPA

04 - OBD I

05 - Does not comply with any OBD requirements

06 - EOBD (European OBD)

Mode 2

In mode 2 the operating conditions (freeze frame data) at the time of fault entry are displayed. The operating conditions of the fault which occurred first are stored. If a fuel system fault or misfiring fault occurs after this, the data of the fault which occurred first are over written.

The following PIDs are supported:

$00 Supported PIDs

The PIDs supported in this mode are displayed in a 4-byte word.

Data A

Fig 12: Identifying $00 Supported PIDs (Data A)

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Data B

Fig 13: Identifying $00 Supported PIDs (Data B)

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Data C

Fig 14: Identifying $00 Supported PIDs (Data C)

Courtesy of PORSCHE OF NORTH AMERICA, INC.

Data D

Fig 15: Identifying $00 Supported PIDs (Data D)

Courtesy of PORSCHE OF NORTH AMERICA, INC.

NOTE: If there is a fault, not all supported PIDs are stored in the memory, but only 6.

The Data A and B bytes indicate that PIDs 02, 03, 04, 05, 06, 07, 08, 09, 0C and 0D are supported. From these supported PIDs, the 6 most meaningful ones are stored for one fault.

$02 Diagnostic Trouble Code

The Diagnostic Trouble Code which caused the storage of freeze frame data is displayed.

$03 Status of injection system

Data:

A: 0000 1000
B: 0000 1000

Data A - Status of bank 1

Data B - Status of bank 2

Bit 0 - Open-loop control, the conditions for closed-loop oxygen sensing have not yet been satisfied.

Bit 1 - Closed-loop control, the signal from the oxygen sensor is used to control injection.

Bit 2 - Open-loop control through conditions such as full load, etc.

Bit 3 - Open-loop control through faults in the system.

Bit 4 - Closed-loop control, but faults from at least one oxygen sensor.

Bits 5 to 7 not used.

NOTE: Only one bit at a time can be set to 1 to indicate the status.

$04 Calculated load value

Output of calculated load as a percentage of the maximum load.

Display between 0% and 100%

$05 Engine coolant temperature

Output of the engine coolant temperature.

Display between - 40 °C and 215 °C.

$06 HO2S integrator, bank 1

Output of the control value FR of the oxygen sensor closed-loop control, bank 1.

Display: lean to - 100%

rich to 99.22%

$07 HO2S adaptation, bank 1

Output of the adaptation value FRA of the oxygen sensor closed-loop control, bank 1.

Display: lean to - 100%

rich to 99.22%

$08 HO2S integrator, bank 2

Output of the control value FR of the oxygen sensor closed-loop control, bank 2.

Display: lean to - 100%

rich to 99.22%

$09 HO2S adaptation, bank 2

Output of the adaptation value FRA of the oxygen sensor closed-loop control, bank 2.

Display: lean to - 100%

rich to 99.22%

$OB Intake manifold pressure (absolute)

Output of the intake manifold pressure:

Display: 0 kPa to 255 kPa

$OC Engine speed

Output of the engine speed.

Display in rpm

$OD Vehicle speed

Output of the speed.

Mode 3

The Diagnostic Trouble Codes of all shedded, officially relevant* faults are displayed in Mode 3.

* Faults which switch on the Check Engine warning light

Mode 4

In Mode 4, the fault memory can be erased.

NOTE: The fault memories of all systems relevant to OBD are erased.

If the fault memory is erased, Mode 5 and Mode 6 values are also reset. Furthermore, the adaptation values are neutralised.

Mode 5

In Mode 5, the values of the last oxygen sensor test carried out (test identification TID) can be read out for every oxygen sensor with its nominal values.

Fig 16: Identifying TID $01-$09

Courtesy of PORSCHE OF NORTH AMERICA, INC.

For the oxygen sensors ahead of the TWC (bank 1/2, sensor 1), the following TIDs are supported:

$01 Rich-lean threshold voltage

Programmed fixed value. e.g. 0.430 V

$02 Lean-rich threshold voltage

Programmed fixed value. e.g. 0.430 V

$07 Minimum voltage of oxygen sensor during the test

Minimum: e.g. 0.025 V

Maximum: e.g. 0.385 V

Test value: e.g. 0.280 V

The specified range within which the voltage must lie and the actual value are displayed.

$08 Maximum voltage of oxygen sensor during the test

Minimum: e.g. 0.475 V

Maximum: e.g. 0.790 V

Test value: e.g. 0.685 V

The specified range within which the voltage must lie and the actual value are displayed.

$09 Time between two transitions

Minimum: e.g. 0.00 s

Maximum: e.g. 1.20 s

Test value: e.g. 0.36 s

The specified range within which the time must lie and the actual value are displayed.

Fig 17: Identifying $09 Time Between Two Transitions

Courtesy of PORSCHE OF NORTH AMERICA, INC.

A - Sensor OK.

B - Shift in sensor characteristic towards lean e.g. due to silicon.

C - Shift in sensor characteristic towards rich e.g. due to lead.

D1 - Amount by which the characteristic has shifted towards lean (PID 31).

D2 - Amount by which the characteristic has shifted towards rich (PID 30).

$30 Shift in oxygen sensor characteristic towards rich

Minimum: e.g. 0.00 s

Maximum: e.g. 1.20 s

Test value: e.g. 0.10 s

The specified range within which the time must lie and the actual value are displayed.

$31 Shift in oxygen sensor characteristic towards lean

Minimum: e.g. 0.00 s

Maximum: e.g. 1.20 s

Test value: e.g. 0.10 s

The specified range within which the time must lie and the actual value are displayed.

$32 Averaged period

Minimum: e.g. 0.32 s

Maximum: e.g. 0.40 s

Test value: e.g. 0.36 s

The specified range within which the time must lie and the actual value are displayed.

NOTE: For the oxygen sensors after the TWC (bank 1/2, sensor 2), only the TIDs $01 to $08 are supported.

Mode 6

The test results of components or systems which are not continuously monitored are displayed in mode 6. At the same time, limit values are provided. The test results are referred to as TID (Test Identification). The components or systems are distinguished by CIDs (Component Identification).

The following components or systems are supported:

TID $01 Catalytic converter monitoring

The catalytic converters (bank 1/bank 2) are monitored individually and for the sum of the emissions. There are two threshold values for individual monitoring:

AHKATMN for O.K. detection and
AHKATMX for fault detection.

For the sum of the emissions, there is the AHKATSB threshold value. A digit (ahkat) which is either 0 or ] is used as a measurement for ageing of the catalytic converters.

0- good

1- bad

Fig 18: Identifying AHKATSB Threshold Value

Courtesy of PORSCHE OF NORTH AMERICA, INC.

The cases for catalytic converter bank 1 are shown in the graphic. The same applies for bank 2.

1 - Catalytic converter 1 O.K.

2 - Catalytic converter 1 O.K.

3 - Catalytic converter 1 O.K.

4 - Catalytic converter 1 faulty (P0420)

5 - Catalytic converters 1 and 2 faulty (P0420 and P0430)

6 - Catalytic converter 1 faulty (P0420)

In the case of the individual CIDs, the limit values (maximum) and the test value of the last test are displayed.

Maximum: fault, if the test value is greater than the limit value.

The following CIDs can be displayed:

$00 Test not yet carried out

$05 Conversion bank 1

The values displayed can be multiplied by the factor 0.0039 to find the ahkat or AHKATMX values.

$06 Conversion bank 2

The values displayed can be multiplied by the factor 0.0039 to find the ahkat or AHKATMX values.

NOTE: CID $05 and $06 are displayed if the test was completed without faults. The values provide information as to how far the catalytic converter are from the limit values.

$07 Checksum error, bank 1 and bank 2

Fault codes P0420 and P0430 in memory.

The values displayed can be multiplied by the factor 0.0078 to find the ahkat]+ahkat2 or AHKATMX values.

$08 Checksum range error, bank 1

Fault code P0420 in memory.

The values displayed can be multiplied by the factor 0.0039 to find the ahkat or AHKATSB values.

$09 Checksum range error, bank 2

Fault code P0430 in memory.

The values displayed can be multiplied by the factor 0.0039 to find the ahkat or AHKATSB values.

$10 Conversion bank 1

The values displayed can be multiplied by the factor 0.0039 to find the ahkat or AHKATMX values.

$11 Conversion bank 2

The values displayed can be multiplied by the factor 0.0039 to find the ahkat or AHKATMX values.

NOTE: CID $10 and $11 are displayed if the function was carried out with the Porsche System Tester 2 in the Short test menu.

TID $03 Secondary air system

The following CIDs can be displayed:

$00 Test not yet carried out

$01 Secondary air system, bank 1

Relative secondary air mass

$04 Secondary air system, bank 2

Relative secondary air mass

NOTE: The relative secondary air mass is the measured secondary air mass relative to the expected nominal value (optimal value) in this operating point.

The optimal value is detected with a faultless system. The nominal value is primarily dependent on exhaust backpressure, geographical altitude and voltage supply.

A fault is present if the relative secondary air mass does not exceed the diagnosis threshold value.

The values displayed can be multiplied by the factor 0.0078 to find the applied values.

TID $05 Fuel tank ventilation system

For the fuel tank ventilation system, several tests are carried consecutively but only one test value is displayed. This means that the subsequent test overwrites the preceding test value.

When all tests have been carried out, $OD (micro-leak test) is displayed.

If a different CID is displayed, the test was interrupted - either because a fault was present or, for example, the EVAP canister was excessively loaded.

The following CIDs can be displayed:

$00 Test not yet carried out

$OA Tank vent valve (leaking)

$OB Shut-off valve, EVAP canister (blocked)

$OC Major leak (pressure increase)

$OD Minor leak (leakage volumetric flow)

$11 Shut-off valve, EVAP canister (pressure reduction)

$12 Major leak (pressure sensor)

$13 Major leak (pressure sensor)

$14 Tank vent valve (constantly open)

Mode 7

The Diagnostic Trouble Codes of all non-shedded, officially relevant* faults are displayed in Mode 7. This mode has the same structure as Mode 3.

* Faults which switch on the Check Engine warning light