2001 BMW 525i fuel control

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- -
On-Board Diagnostics
Professional diagnostic scan tools available atthe time of this
printing include the BMW factory tools
(DISplus, GTI,
MoDiC) and a small number of aftermarket BMW-specific
tools. See
020 Maintenance.
In addition to the professional line of scan tools, inexpensive
generic OBD
II scan tool software programs and handheld
units are readily available. Though limited, they are
nonetheless powerful diagnostic tools. These tools read live
data streams and freeze frame data as well as a host of other
valuable diagnostic data.
Diagnostic monitors
Diagnostic monitors run tests and checks on specific
emission control systems, components, and functions.
A complete drive cycle is requiredforthe tests to bevalid. See
Drive cycle in this repair group. The diagnostic monitor
signals the
ECM of the loss or impairment of the signal or
component and determines if a signal or sensor is faulty
based on
3 conditions:
* Signal or component shorted to ground
Signal or component shorted to
B+
Signal or component missing (open circuit)
The OBD
II system monitors all emission control systems that
are installed. Emission control systems vary by vehicle model
and year. For example, a vehicle may not be equipped with
secondary air injection, so no secondary air readiness code
would be present.
OBD
II software monitors the following:
Oxygen sensors
Catalysts
Engine misfire
- Fuel tank evaporative control system
Secondary air injection Fuel system
Oxygen sensor monitoring. When driving conditions allow,
response rate and switching time of each oxygen sensor is
monitored. The oxygen sensor heater function is also
monitored. The OBD
II system differentiates between
precataylst and post-catalyst oxygen sensors and reads each
one individually. In order
forthe oxygen sensor to be
effectively monitored, the system must be in closed loop
operation.

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OBD-6
On-Board Diagnostics
Fuel system monitoring. This monitor looks at the fuel
delivery needed (long
/short term fuel trim) for proper engine
operation based on programmed data. If too much or not
enough fuel is delivered over a predetermined time, a DTC is
set and the MIL illuminates.
Fuel trim refers to adiustments to base fuel schedule.
Lono- ., term fuel trim refers to gradual adjustments to the fuel
calibration adjustment as compared to short term fuel trim.
Long term fuel trim adjustments compensate for gradual
changes that occur over time.
Fuel system monitoring monitors the calculated injection time
(ti) in relation to enginespeed, load and precatalyticconverter
oxygen
sensor(s) signals.
Using this data, the system optimizes fuel delivery for all
engine operating conditions.
Evaporative system monitoring. This monitor checks the
the fuel storage system and related fuel lines for leaks. It can
detect very small leaks anywhere in the system.
A leak detection unit (LDP or DMTL) is used to pressurize the
evaporative control system on a continuous basis (as the
drive cycle allows) and to
check system integrity.
Drive cycle
The OED II drive cycle is an important concept in
understanding OBD
II requirements. The purpose of the drive
cycle is to run ail of the emission-related on-board diagnostics
over a broad range of driving conditions.
A drive cycle is considered complete when all of the
diagnostic monitors have run their tests without interruption.
~ora drive cycle to be initiated, the vehicle must be started
cold and brought up to
1 60°F and at least 40°F above its
original starting temperature.
Readiness codes
Inspection/maintenance (I/M) readiness codes are mandated
as part of OBD
II. The readiness code is stored aftercomplete
diagnostic monitoring of specified components and systems
is carried out. The readiness code function was designed to
prevent manipulating an
I/M emission test procedure by
clearing faults codes or disconnecting the ECM or battery.

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On-Board Diagnostics
Readiness codes indicate whether the OED Ii system is
actually ready to monitor the various emission control
systems on the vehicle. The vehicle must complete a drive
cycle to set readiness codes. The code is binary:
0 for ready
1 for not ready
f
4 The parameters which are monitored for readiness are:
llM readiness codes
1. Catalyst efficiency
2. Catalyst heating
3. Fuel tank evaporative control
4. Secondary air injection
5.
NC refrigerant
6. Oxygen sensors
7. Oxygen sensor heaters
8. Exhaust gas recirculation
Readiness codes are set to 1 (not ready) in the following
cases:
~9~~.f~[<+t~t~p:,~;:#j~~{]~y~ ,,... , , 8701Dbd001
The battery or ECM is disconnected.
When
all zeros are displayed, the system has established
DTCs are erased after completion of repairs and a drive
cycle is not completed.
readiness. Readiness codes
can be displayed using BMW
and aftermarket scan tools.
An
OED II scan tool can be used to determine IIM readiness.
Diagnostic trouble codes (DTCs)
SAE standard J2012 mandates a 5-digit diagnostic trouble
code (DTC) standard. Each digit represents a specific value.
Emission related DTCs
start with the letter P for power train.
When the engine service
light (MIL) is illuminated it indicates
that a DTC has been stored.
DTCs are stored as soon as they occur, whether or not the
engine service light illuminates.
DTCs store and display a time stamp.
DTCs record the current fault status: Present, not currently
present, or intermittent.

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OBD-8
I On-Board Diagnostics
DTC digit interpretation
1st digit
P powertrain
B body
C chassis
2nd digit
0 SAE
1 BMW
3rd digit
0
1
2
3
4
5
6
7
4th - 5th digits total
system
airlfuei induction
fuel injection
ignition system or misfire
auxiliary emission control
vehicle speed
& idle control
ECM
inputs/outputs
transmission
individual circuits or
components
DTC example: P 0 3 0 6
P: A powertrain problem
0: SAE sanctioned or 'generic'
a 3: Related to an ignition system / misfire
06 Misfire detected at cylinder #6
DTCs provide a freeze frame or snap-shot of a vehicle
performance or emissions fault at the moment that the fault
first occurs. This information is accessible through generic
OED I1 scan tools.
Freeze frame data contains, but is not limited to, the following
information:
Engine load (calculated)
Engine rpm
Short and
long term fuel trim
Vehicle speed
Coolant temperature Intake manifold pressure
Open/closed loop operation
Fuel pressure (if available)
DTC

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OBD-15
On-Board ~iagnosticsl
Engine diagnostic trouble codes: M52 engine (continued)
P-code
PO340
PO412
PO420
PO430
PO440
PO441
PO442
PO443
PO500
PO505
PO600
PO601
PO601
I PO601
~1132
~1133
BMW-FC
65
62
233
234
250 144
-
145
68
214
i I
DTC Definition
Camshalt Position Sensor 'A' Circuit (Bank 1 or Single Sensor)
Secondary Air Injection System Switching Valve A Circuit
Catalyst System Efficiency Below Threshold
(Bank 1)
Catalyst System Efficiency Below Threshold (Bank 2)
Evaporative Emission System
Eva~orative Emission Svstem Incorrect Purge Flow .
Evaporative Emission System Leak Detected (small leak)
Evaporative Emission System Purge Control Valve Circuit
Vehicle Speed Sensor 'A'
204
21 7
100
170
171
188
189
PI161
PI180
PI181
PI184
PI185
PI178
02 Sensor Heater Control Circuit (Bank 2 Sensor 2) I
idle Air Control System
Serial Communication
Link
Internal Control Module Memory Check Sum Error
Internal Control Module Memory
Check Sum Error
Internal Control Module Memory
Check Sum Error
02 Sensor Heater Control Circuit (Bank 1 Sensor
1)
02 Sensor Heater Control Circuit (Bank 2 Sensor 1)
Mass or Volume Air Flow Circuit RangeIPerlormance Problem PI140
I
I I
P1188 1227 I Fuel Control (Bank 1 Sensor 1)
PI145 150 /Solenoid Valve Running Losses Control Circuit Electrical
149
122
223
224
220 221
231
I I
P1189 1228 I Fuel Control (Banlc 2 Sensor 1)
Fuel Trim Adaptation Additive High (Bank 2) (M52: Engine Oil Temperature Sensor Circuit)
02 Sensor Signal Circuit Slow Switching from Rich to Lean
(Bank 1 Sensor 2)
02 Sensor Signal Circuit Slow Switching from Rich to Lean
(Bank 2 Sensor 2)
H02S Sensor Voltage Excursion Electrical (Banlc 1 Sensor 1)
HO2S Sensor Voltage Excursion Electrical (Banlc 2 Sensor 1)
02 Sensor Sianai Circuit Slow Switchina from Rich to Lean (Bank 1 Sensor 1)
02 Sensor Signal Circuit Slow Switching from Rich to Lean (Bank 2 Sensor 1) PI179
I I
PI190 1235 I Pre Catalyst Fuel Trim System (Banlc 1)
PI186 1190 102 Sensor Heater Control Circuit (Banlc 1 Sensor 2)
232
I I
PI191 1236 I Pre
Catalyst Fuel Trim System (Banlc 2)
PI192
. . -- - i Pi193 1226 I Post Catalvst Fuel Trim Svstem (Bank 2)
225
PI397
I I
Post Catalyst Fuel Trim System (Bank 1)
PI421 1246 /Secondarv Air System (Bank 2)
18
Secondary Air System (Bank
1) PI423
Camshaft Position Sensor '0' Circuit (Bank 1)
I 245

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I On-Board Diagnostics
Engine diagnostic trouble codes: M54 engine (continued)
P-code
BMW-FC Explanation
Catalyst System Efficiency Below Threshold (Bank 2)
PO430
PO443
PO444
PO445
PO455
PO456
PO491
PO492
PO500
PO441 1250 / Evaporative Emission System Incorrect Purge Flow
234
I I
68
68
68 143
143
245
246
214
PO604
PI083
PI084
PI085
PI086
Evaporative Emission System Purge Control Valve Circuit
Evaporative Emission System Purge Control Valve Circuit Open
Evaporative Emission System Purge Control Valve Circuit Shorted
Evaporative Emission System Leak Detected (large leak)
Evaporative Emission System Leak Detected (very
small leak)
Secondary Air injection System Insufficient Flow (Bani( 1)
Secondary Air Injection System insufficient Flow
(Banic 2)
Vehicle Speed Sensor
'A'
Idle Air Control System PO505
.
PI 087
PI 088
PI089
PI090
PO600 / 217 I Serial Communication Link
204
100
202
202
203
203
PI091
PI092
PI093
PI094
Pllll
PI112
PI120
Internal Control Module Random Access Memory (RAM) Error
Fuel Control Limit Mixture Too Lean (Bank 1 Sensor
1)
Fuel Control Limit Mixture Too Rich (Bank 1 Sensor 1)
Fuel Control Limit Mixture Too Lean (Bank 2 Sensor 1)
Fuel Control Limit Mixture Too Rich (Banic 2 Sensor 1) ~ ~
229
229
230 235
PI121
PI122
PI123
02 Sensor Circuit Slow Response in Lean Control Range (Bank 1 Sensor 1)
02 Sensor Circuit Slow Response in Rich Control Range (Bank 1 Sensor
1)
02 Sensor Circuit Slow Response in Lean Control Range (Banlc 1 Sensor 2)
Pre Catalyst Fuel Trim System Too Lean
(Bank 1)
236
235
236
230
11
11
114
PI134
PI135
PI136
PI137
PI138
Pre Catalyst Fuel Trim System Too Lean (Banic 2)
Pre Catalyst Fuel Trim System Too Rich
(Bank 1)
Pre Catalyst Fuel Trim System Too Rich (Bank 2)
02 Sensor Circuit Slow Response in Rich Control Range (Banic 2 Sensor 1)
Engine Coolant Temperature Sensor Radiator Outlet Low Input
Engine Coolant Temperature Sensor Radiator Outlet High Input
Pedal Position Sensor Circuit
117
110
110
25
25
25
79
79 Pedal Position Sensor 1
RangeIPerformance Problem
Pedal Position Sensor 1 Low Input
Pedal Position Sensor 1 High Input
02 Sensor Heater Circuit Signal Intermittent (Bank 1 Sensor 1)
02 Sensor Heater Circuit Low Voltage (Bank 1 Sensor
1)
02 Sensor Heater Circuit High Voltage (Bank 1 Sensor 1)
02 Sensor Heater Circuit Signal Intermittent (Bank 1 Sensor 2)
02 Sensor Heater Circuit Low Voltage
(Banic 1 Sensor 2)
-
-

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/ On-Board Diaanostics I
Engine diagnostic trouble codes: M62 engine
P-code
PO01 1
PO012
PO020
PO021
PO022
PO030
PO031
PO032
I I
PO038 / 14 I H02S Heater Control Circuit High (Bank 1 Sensor 2)
PO010 / 33 / 'A' Camshaft Position Actuator Circuit (Bank 1)
BMW-FC
I I -.
Explanation
33
33
34
34
34 13
13
13
PO36
'A' Camshaft Position Timing Over-Advanced or System Performance (Bank 1)
'A' Camshaft Position Timing Over-Retarded (Bank 1)
'A' Camshaft Position Actuator Circuit (Bank 2)
'A' Camshaft Position Timing Over-Advanced or System Performance (Banlc 2)
'A' Camshaft Position Timing Over-Retarded (Banlc 2)
H02S Heater Control Circuit (Bank 1 Sensor 1)
H02S Heater Control Circuit Low (Bank 1 Sensor 1)
HOPS Heater Control Circuit Hiqh (Banlc 1 Sensor 1)
PO050
PO051
PO052
PO056
PO057
PO058
PO037 / 14 / H02S Heater Control Circuit Low (Bank 1 Sensor 2)
14
I I -.
Ir-1 ThrottleIPedal Position SensorISwitch 'A' Circuit
Low-
HO2S Heater Control Circuit (Bank 1 Sensor 2)
5
5
5
4
4
4
PO102
PO1 13
PO116
PO117
PO118
PO119
PO120
PO121
H02S Heater Control Circuit (Banlc 2 Sensor 1)
H02S Heater Control Circuit Low (Bank 2 Sensor 1)
H02S Heater Control Circuit High (Bank 2 Sensor 1)
H02S Heater Control Circuit (Bank 2 Sensor 2)
HO2S Heater Control Circuit Low (Bank 2 Sensor 2)
HO2S Heater Control Circuit Hiqh (Bank 2 Sensor 2)
PO103 1115 I Mass or Volume Air Flow Circuit High Input
115
124
123
123
123
123
117
118
PO1 23
PO125
PO128
PO1 30
PO131
POI 32
PO133
Mass or Volume Air Flow Circuit Low Input
lntalte Air Temperature Sensor 1 Circuit High
Engine Coolant Temperature Circuit
RangeIPerlormance
Engine Coolant Temperature Circuit Low
Engine Coolant Temperature Circuit High
Engine Coolant Temperature Circuit Intermittent
ThrottleIPedal Position SensorISwitch 'A' Circuit
ThrottieIPedal Position SensorISwitch 'A' Circuit RanqeIPerformance
118
123 139
10
10
10
15
ThrottleIPedai Position SensorlSwitch 'A' Circuit High
insufficient Coolant Temperature for Closed Loop Fuel Control
Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
02 Sensor Circuit (Bank
1 Sensor 1)
02 Sensor Circuit Low Voltage (Bank 1 Sensor 1)
02 Sensor Circuit High Voltage (Bank
1 Sensor 1)
02 Sensor Circuit Slow Response (Bank 1 Sensor
1)

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On-Board ~ia~nosticsl
I I
PO340 1113 I Camshaft Position Sensor 'A' Circuit (Bank 1 or Single Sensor)
Engine
diagnostic trouble codes:
M62 engine (continued)
P-code
PO342
PO343
PO345
PO347
PO348
PO363
PO370
PO41 2
PO335 I111 I Crankshaft Position Sensor 'A' Circuit
BMW-FC
I I -
I I -
PO445 1 98 1 Evaporative Emission System Purge Control Valve Circuit Shorted
Explanation
113
113
114
114
114
62 112
85
PO41 3
PO41 8
PO420
PO430
PO440
PO442
PO442
PO443
PO444
Camshaft Position Sensor 'A' Circuit Low (Bank 1 or Single Sensor)
Camshaft Position Sensor
'A' Circuit High (Bank 1 or Single Sensor)
Camshaft Position Sensor
'A' Circuit (Bank 2)
Camshaft Position
Sensor'A' Circuit Low (Bank 2)
Camshaft Position Sensor 'A' Circuit High
(Banic 2)
Misfire Detected
- Fueling Disabled
Timing Reference High Resolution Signal
'A'
Secondary Air lniection System Switchinq Valve A Circuit
PO41 4 / 85 I Secondary Air Injection System Switching Valve A Circuit Shorted
85
84
40
45 93 183
188
98
98
PO450
PO452
PO453
PO455
PO456
PO491
PO492
PO500
PO506
I I
PI102 1163 I Idle Control System, Adaptation of Unmetered Air Mass Too Low
Secondary
Air Injection System Switching Valve A Circuit Open
Secondary Air Injection System Control
'A' Circuit
Catalyst System Efficiency Below Threshold (Bank 1)
Catalyst System Efficiency
Below Threshold (Bank 2)
Evaporative Emission System
Evaporative Emission System Leak Detected (small
leak)
Evaporative Emission System Leak Detected (small leak)
Evaporative Emission System Purge Control Valve Circuit
Evaporative Emission System Purqe Control Valve Circuit Open
I
I
185
185
185
183
187
80
81 120
32
PO507
Evaporative Emission System Pressure SensorISwitch
Evaporative Emission System Pressure SensorISwitch Low
Evaporative Emission System Pressure
SensorISwitch High
Evaporative Emission System
Leaic Detected (large leak)
Evaporative Emission System
Leal$ Detected (very small leak)
Secondary Air Injection System Insufficient Flow (Bank
1)
Secondary Air Injection System insufficient Flow (Bank 2)
Vehicle Speed Sensor
'A'
idle Air Control System RPM Lower Than Expected
PI103
PI130
PI131
PO600 1 220 I Serial Communication Link
32
idle Air
Control System RPM Higher Than Expected
163
17
23
Idle Control System, Adaptation of Unmetered Air Mass Too Large
02 Sensor Circuit Dynamic Test (Bank
1 Sensor 2)
02 Sensor Circuit Dynamic Test (Bank 2 Sensor 2)