Volkswagen New Beetle. Manual - part 1812

 

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Volkswagen New Beetle. Manual - part 1812

 

 

Fig. 16: Identifying Heated Oxygen Sensor Harness Connector Terminals - Downstream TWC 
Courtesy of VOLKSWAGEN UNITED STATES, INC. 

DTC P0101/16485, P0102/16486 & P0103/16487: MAF SENSOR 

Code Definition 

DTC P0101/16485 
MAF Sensor (G70) - Implausible Signal 

DTC P0102/16486 
MAF Sensor (G70) - Voltage Signal To Low 

DTC P0103/16487 
MAF Sensor (G70) - Voltage Signal To High 

 

2003 Volkswagen New Beetle GLS 

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

  

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Page 48 

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Test Requirements 

Ensure all fuses are okay, battery voltage is at least 11.5 volts and fuel pump relay is okay. Ensure all electrical 
accessories are off and A/C is off. Ensure engine is mechanically sound. Ensure no exhaust system leaks exist. 
Ensure engine coolant temperature is at least 176°F (80°C). On vehicles with M/T, gear shifter must be in 
neutral with parking brake set. On vehicles with A/T, selector lever must be in park or neutral with parking 
brake set.  

Test Procedure 

1. Inspect air induction system for leaks. Check air filter Check air filter for blockage. Repair as necessary. 

After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See 
TEST DRIVE RELEARN PROCEDURE .  

2. Connect scan tool. See RETRIEVING DIAGNOSTIC TROUBLE CODES . Start engine and idle. 

Using scan tool, check air mass drawn in by engine. Air mass should be 2.0-5.0 grams/second at idle. If 
air mass reading is okay, go to next step (voltage supply for MAF sensor must be checked). If air mass 
reading is not okay, go to step 6 .  

3. Turn ignition off. Disconnect MAF sensor 5-pin connector. Start engine and idle. Using DVOM, measure 

voltage between MAF sensor 5-pin connector, terminal No. 2 and ground. See Fig. 18 . Voltage should 
be 11-15 volts. If voltage is okay, go to step 5 . If voltage is not okay, go to next step.  

4. Turn ignition off. Repair wiring from MAF sensor 5-pin connector, terminal No. 2 and fuel pump relay 

(J17). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. 
After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See 
TEST DRIVE RELEARN PROCEDURE .  

5. Turn ignition on. Using DVOM, check voltage between MAF sensor 5-pin connector, terminal No. 4 and 

ground. See Fig. 18 . Voltage should be 4.5-5.5 volts. If voltage is okay, go to next step (further circuit 
tests are required). If voltage is not okay, go to next step.  

6. Turn ignition off. Disconnect ECM harness connector, leave ECM disconnected from test box. Connect 

Test Box (VAG 1598/31) to ECM harness connector. See CONNECTING VAG TEST BOX . Using 
DVOM, check resistance between the following MAF sensor (G70) connector terminals and test box 
sockets. See Fig. 18 . 

z

MAF sensor harness connector terminal No. 3 and test box socket No. 27.  

z

MAF sensor harness connector terminal No. 4 and test box socket No. 53.  

z

MAF sensor harness connector terminal No. 5 and test box socket No. 29.  

Resistance should be a maximum of 1.5 ohms for each reading. If resistance measurements are okay, go 
to next step. If any resistance measurement is not okay, repair circuit(s) as necessary. After repairs, erase 
DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 
.  

7. Using DVOM, check wiring in MAF sensor 5-pin connector for short circuit to one another, short circuit 

to ground, and short circuit to B+. Repair as necessary. After repairs, erase DTC memory. Verify repair. 
Test is complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE . If 
circuits are okay, go to next step.  

8. If all wiring, voltage checks, and grounds are okay, and DTC P0101/16485, DTC P0102/16486 or DTC 

P0103/16487 return, replace faulty MAF sensor (G70). After repairs, erase DTC memory. Verify Repair. 
Test is complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE 

 

2003 Volkswagen New Beetle GLS 

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

  

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DTC P0112/16496 & P0113/16497: IAT SENSOR 

Code Definition 

DTC P0112/16496 
IAT Sensor (G42) - Signal Too Low 

DTC P0113/16497 
IAT Sensor (G42) - Signal Too High  

Test Requirements 

Ensure all fuses are okay, battery voltage is at least 11.5 volts and fuel pump relay is okay. Ensure all electrical 
accessories are off and A/C is off. Ensure engine is mechanically sound. Ensure no intake or exhaust system 
leaks exist. On vehicles with M/T, gear shifter must be in neutral with parking brake set. On vehicles with A/T, 
selector lever must be in park or neutral with parking brake set.  

Test Procedure 

1.  

Disconnect MAF/IAT sensor harness connector, (MAF/IAT sensor is located in air intake duct assembly 
next to air cleaner). Using DVOM, measure resistance of IAT sensor between MAF/IAT sensor terminals 
No. 1 and 3. See Fig. 17 . See IAT SENSOR RESISTANCE table. If IAT sensor resistance is okay, 
reconnect MAF/IAT sensor harness connector. Go to next step. If resistance is not okay, replace faulty 
MAF/IAT sensor. After repairs, erase DTC memory. Verify repair. Test is complete. Perform ECM 
relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

2. Connect Scan Tool. See RETRIEVING DIAGNOSTIC TROUBLE CODES . Go to next step.  

3. Turn ignition on. Using scan tool, check IAT sensor temperature value. If IAT sensor temperature value 

NOTE:

If a test ends with ECM replacement, before replacing ECM be certain that, all 
wiring, power and ground supplies are okay. See ENGINE PERFORMANCE in 
SYSTEM WIRING DIAGRAMS article in ELECTRICAL and ECM GROUND & 
VOLTAGE SUPPLY . 

NOTE:

If sensor or wiring is defective, ECM operates with a substitute intake air 
temperature of 67.1°F (19.5°C). For harness connector terminal wire colors, see 
ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in 
ELECTRICAL. 

NOTE:

Engine must be cold before performing test procedure. 

NOTE:

When viewing/testing IAT sensor resistance on MAF/IAT sensor terminals 
pay particular attention to position of MAF/IAT sensor and terminal 
number/orientation for IAT sensor (there is a squared and a rounded end 
at exterior of MAF/IAT terminal housing). See Fig. 17 . 

 

2003 Volkswagen New Beetle GLS 

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

  

Helpmelearn Repair Manuals 

 

Wednesday, December 14, 2005 8:49:55 AM

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© 2004 Mitchell Repair Information Company, LLC. 

deviates greatly from underhood ambient temperature, go to step 6 . If IAT sensor temperature value is 
approximately the same as underhood ambient temperature, go to next step.  

4.  

Turn ignition off. Disconnect MAF/IAT sensor harness connector from MAF/IAT sensor. Remove 
MAF/IAT sensor. Reconnect MAF/IAT sensor harness connector. Turn ignition on. Using a chilling 
agent, cool IAT sensor. Using scan tool, observe IAT sensor temperature value. Temperature value 
should steadily decrease. If IAT sensor temperature value steadily decreased. Go to next step. If IAT 
sensor temperature value did not steadily decrease, replace faulty MAF/IAT sensor. Erase DTC memory. 
Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN 
PROCEDURE 
.  

5. Erase DTC memory. Test drive vehicle. If DTC P0112/16496 or DTC P0113/16497 returns, go to step 9 . 

If DTC P0112/16496 or DTC P0113/16497 does not return, test is complete. Perform ECM relearn 
procedure. See TEST DRIVE RELEARN PROCEDURE .  

6. If IAT sensor temperature value is extremely low, approximately -40°F (-40°C), possible cause is open 

circuit or short to B+. Turn ignition off. Go to next step. If IAT sensor temperature value is extremely 
high, approximately 284°F (140°C), possible cause is short to ground. Turn ignition off. Go to step 8 .  

7. Disconnect MAF/IAT sensor harness connector. For MAF/IAT sensor location. Using a jumper wire, 

bridge MAF/IAT sensor harness connector terminals No. 1 and 3. See Fig. 18 . Turn ignition on. Using 
scan tool, observe IAT sensor temperature value. If IAT sensor temperature value is approximately -40°F 
(40°C), turn ignition off. Go to step 9 . If IAT sensor temperature value is approximately 284°F (140°C), 
turn ignition off. Replace faulty MAF/IAT sensor. Erase DTC memory. Verify repair. Test is complete. 
Perform ECM relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

8. Disconnect MAF/IAT sensor harness connector. Turn ignition on. Using scan tool, observe IAT sensor 

temperature value. If after disconnecting MAF/IAT sensor harness connector, temperature value is 
approximately -40°F (-40°C), turn ignition off. Replace faulty IAT sensor. Erase DTC memory. Verify 
repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE RELEARN 
PROCEDURE 
. If after disconnecting MAF/IAT sensor harness connector, temperature value is 
approximately 284°F (140°C), turn ignition off. Go to next step.  

9. Disconnect ECM harness connector, leave ECM disconnected from test box. Connect Test Box (VAG 

1598/31) to ECM harness connector. See CONNECTING VAG TEST BOX . Disconnect MAF/IAT 
sensor harness connector. Using DVOM, measure resistance between MAF/IAT sensor harness connector 
terminal No. 1 and test box socket No. 26. See Fig. 18 . Record resistance reading. Using DVOM, 
measure resistance between MAF/IAT sensor harness connector terminal No. 3 and test box socket No. 
27. Record resistance reading. Resistance should be a maximum of 1.5 ohms for each reading. Go to next 
step.  

10. Check MAF/IAT sensor harness connector terminal No. 1 and 3 for short circuit to battery positive and 

ground. Also verify MAF/IAT sensor harness connector circuits are not shorted to each other. Repair 
wiring harness as necessary. Erase DTC memory. Verify repair. Test is complete. Perform ECM relearn 
procedure. See TEST DRIVE RELEARN PROCEDURE . If wiring and IAT sensor are okay, replace 
faulty ECM. See ENGINE CONTROL MODULE REMOVAL & INSTALLATION . Erase DTC 
memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 
.  

NOTE:

Next test step tests IAT sensor through its full range. 

 

2003 Volkswagen New Beetle GLS 

2001-2003 ENGINE PERFORMANCE Self-Diagnostics - 2.0L - Beetle, Golf & Jetta (Engine Codes AVH & AZG)

  

Helpmelearn Repair Manuals 

 

Wednesday, December 14, 2005 8:49:55 AM

Page 51 

© 2004 Mitchell Repair Information Company, LLC. 

 

 

 

 

 

 

 

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