Volkswagen New Beetle. Manual - part 1862

 

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Volkswagen New Beetle. Manual - part 1862

 

 

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

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

deviates greatly from underhood ambient temperature, go to step 5 . If IAT sensor temperature value is 
approximately the same as underhood ambient temperature, go to next step.  

3.  

Turn ignition off. Disconnect IAT sensor harness connector. For IAT sensor location. See 
COMPONENT LOCATIONS . Remove IAT sensor from intake plenum. Reconnect 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 IAT sensor. Erase DTC memory. Verify repair. Test is complete. Perform ECM relearn 
procedure. See TEST DRIVE RELEARN PROCEDURE .  

4. Erase DTC memory. Test drive vehicle. If DTC P0112/16496 or DTC P0113/16497 returns, go to step 8 . 

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

5. If IAT sensor temperature value is extremely low, approximately -50°F (-46°C), possible cause is open 

circuit or short to positive. Go to next step. If IAT sensor temperature value is extremely high, 
approximately 285°F (141°C), possible cause is short to ground. Go to step 7 .  

6. Disconnect IAT sensor harness connector. For IAT sensor location. See COMPONENT LOCATIONS 

Using a jumper wire, bridge IAT sensor harness connector terminals No. 1 and 2. Using scan tool, 
observe IAT sensor temperature value. If IAT sensor temperature value is approximately -50°F (46°C), 
turn ignition off. Go to step 8 . If IAT sensor temperature value is approximately 285°F (141°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 .  

7. Disconnect IAT sensor harness connector. For IAT sensor location. See COMPONENT LOCATIONS 

Using scan tool, observe IAT sensor temperature value. If after disconnecting IAT sensor harness 
connector, temperature value is approximately -50°F (-46°C), turn ignition off. Replace faulty IAT 
sensor. Erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST 

temperature of 67.1°F (19.5°C). For harness connector terminal wire colors, see 
appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM 
WIRING DIAGRAMS. 

NOTE:

Engine must be cold before performing test procedure. 

NOTE:

Next test step tests IAT sensor through its full range. 

 

2003 Volkswagen New Beetle GLS 

2002-2003 ENGINE PERFORMANCE Self-Diagnostics - 1.8L Turbo

  

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DRIVE RELEARN PROCEDURE . If after disconnecting IAT sensor harness connector, temperature 
value is approximately 285°F (141°C), turn ignition off. Go to next step.  

8. 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 IAT sensor 
harness connector. Using DVOM, measure resistance between IAT sensor harness connector terminal No. 
1 and test box socket No. 85. See Fig. 17 . Record resistance reading. Using DVOM, measure resistance 
between IAT sensor harness connector terminal No. 2 and test box socket No. 108. Record resistance 
reading. Resistance should be a maximum of 1.5 ohms for each reading. Go to next step.  

9. Check IAT sensor harness connector terminal No. 1 for short circuit to battery positive and ground. 

Check IAT sensor harness connector terminal No. 2 for short circuit to battery positive. Also verify 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 .  

IAT SENSOR RESISTANCE 

DTC P0116/16500, DTC P0117/16501 & DTC P0118/16502 

Code Definition 

z

DTC P0116/16500: ECT Sensor (G62) - Implausible Signal  

z

DTC P0117/16501: ECT Sensor (G62) - Signal Too Low  

z

DTC P0118/16502: ECT Sensor (G62) - 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. Ensure engine coolant system and engine coolant system thermostat are in good working order. 

Temperature - °F (°C) 

Ohms 

86 (30) 

1500-2000 

104 (40) 

1000-1500 

122 (50) 

800-1000 

140 (60) 

500-700 

158 (70) 

375-500 

176 (80) 

275-375 

194 (90) 

225-275 

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 . 

 

2003 Volkswagen New Beetle GLS 

2002-2003 ENGINE PERFORMANCE Self-Diagnostics - 1.8L Turbo

  

Helpmelearn Repair Manuals 

 

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Test Procedure - Beetle (Engine Code AWV) 

1. Disconnect ECT sensor harness connector. See Fig. 26 . Using DVOM, measure resistance of ECT sensor 

between ECT sensor terminals No. 1 and 3. See Fig. 27 . See ECT SENSOR (G62) RESISTANCE 
table. If ECT sensor resistance is okay, reconnect ECT sensor harness connector. Go to next step. If 
resistance is not okay, replace faulty ECT sensor. 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 . Turn ignition on. Using 

scan tool, check ECT sensor temperature value. If ECT sensor temperature value deviates greatly from 
ECT sensor ambient temperature, go to step 4 . If ECT sensor temperature value is approximately the 
same as ECT sensor ambient temperature, go to next step.  

3.  

Start engine and idle. Using scan tool, observe ECT sensor temperature value. Temperature value should 
steadily increase. If ECT sensor temperature value did not steadily increase, replace faulty ECT sensor. 
Erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 
.  

4. If ECT sensor temperature value is extremely high, approximately 285°F (141°C), possible cause is short 

to ground. Go to step 6 . If ECT sensor temperature value is extremely low, approximately -50°F (-46°C), 
possible cause is open circuit or short to positive. Go to next step.  

5. Disconnect ECT sensor harness connector. See Fig. 26 . Using a jumper wire, bridge terminal with 

Brown/Blue wire and terminal No. 3 of ECT sensor harness connector. See Fig. 28 . Connect Scan Tool. 
See RETRIEVING DIAGNOSTIC TROUBLE CODES . Using scan tool, observe ECT sensor 
temperature value. If ECT sensor temperature value is approximately -50°F (46°C), turn ignition off. Go 
to step 7 . If ECT sensor temperature value is approximately 285°F (141°C), turn ignition off. Replace 
faulty ECT sensor. Erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. 
See TEST DRIVE RELEARN PROCEDURE .  

6. Disconnect ECT sensor harness connector. See Fig. 26 . Using scan tool, observe ECT sensor 

WARNING:

To avoid injury, allow cooling system to cool and carefully release system 
pressure. 

NOTE:

Engine must be cold before performing test procedure. 

NOTE:

To bleed cooling system, fill cooling system. Warm engine to operating 
temperature, (run engine until coolant fan starts), do not allow engine to 
overheat, let engine cool and recheck coolant level. 

NOTE:

Next test step tests ECT sensor through its full range. 

NOTE:

Scan Tool (VAG 1551) and (VAG 1552) displays temperature in 1 to 1.5 
degree increments. If engine does not run smoothly in certain temperature 
ranges and temperature value does not increase without interruption, 
signal is intermittent. ECT sensor must be replaced. After repairs, erase 
DTC memory. 

 

2003 Volkswagen New Beetle GLS 

2002-2003 ENGINE PERFORMANCE Self-Diagnostics - 1.8L Turbo

  

Helpmelearn Repair Manuals 

 

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temperature value. If after disconnecting ECT sensor harness connector, temperature value is 
approximately 285°F (141°C), turn ignition off. Go to next step. If after disconnecting ECT sensor 
harness connector, temperature value is approximately -50°F (-46°C), turn ignition off. Replace faulty 
ECT sensor. Erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See 
TEST DRIVE RELEARN PROCEDURE .  

7. 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 ECT sensor 
4-pin harness connector. See Fig. 26 . Using DVOM, measure resistance between ECT sensor harness 
connector terminal with Brown/Blue wire and test box socket No. 108. See Fig. 28 . Record resistance 
reading. Measure resistance between ECT sensor harness connector terminal No. 3 and test box socket 
No. 93. Record resistance reading. Resistance should be a maximum of 1.5 ohms for each reading. Go to 
next step.  

8. Check ECT sensor harness connector terminal No. 3 for short circuit to test box socket No. 108. Check 

ECT sensor harness connector terminal No. 3 sensor for short circuit to battery positive and ground. 
Check Brown/Blue wire on ECT sensor harness connector for short circuit to B+. Repair as necessary. 
Erase DTC memory. Verify repair. Test is complete. Perform ECM relearn procedure. See TEST DRIVE 
RELEARN PROCEDURE 
. If wiring and ECT 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 .  

Test Procedure - Beetle, GTI & Jetta (Engine Code AWP) 

1. Disconnect ECT sensor harness connector. See Fig. 29 . Using DVOM, measure resistance of ECT sensor 

between ECT sensor terminals C and D. See Fig. 30 and ECT (G62) SENSOR RESISTANCE table. If 
ECT sensor resistance is okay, reconnect ECT sensor harness connector. Go to next step. If resistance is 
not okay, replace faulty ECT sensor. Erase DTC memory. Verify repair. Test is complete. Perform ECM 
relearn procedure. See TEST DRIVE RELEARN PROCEDURE .  

2. Verify battery voltage is a minimum of 11.5 volts and all fuses are okay. Repair as necessary. Turn 

ignition on. Using scan tool, check ECT sensor temperature value. If ECT sensor temperature value 
deviates greatly from ECT sensor ambient temperature, go to step 4 . If ECT sensor temperature value is 
approximately the same as ECT sensor ambient temperature, go to next step.  

3.  

WARNING:

To avoid injury, allow cooling system to cool and carefully release system 
pressure. 

NOTE:

Engine must be cold before performing test procedure. 

NOTE:

To bleed cooling system, fill cooling system. Warm engine to operating 
temperature, (run engine until coolant fan starts), do not allow engine to 
overheat, let engine cool and recheck coolant level. 

NOTE:

Next test step tests ECT sensor through its full range. 

NOTE:

Scan Tool (VAG 1551/1552) and (VAS 5051/5052) displays temperature in 1 

 

2003 Volkswagen New Beetle GLS 

2002-2003 ENGINE PERFORMANCE Self-Diagnostics - 1.8L Turbo

  

Helpmelearn Repair Manuals 

 

Wednesday, December 14, 2005 8:44:34 AM

Page 73 

© 2004 Mitchell Repair Information Company, LLC. 

 

 

 

 

 

 

 

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