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2004 Pontiac Sunfire with DTC 0507 and 0717: IAC and Input/Turbine Speed Sensor Issues

Model: Pontiac Sunfire Fault Code: P0507 Posted: 2009-05-11 22:11

Vehicle: 2004 Pontiac Sunfire, 2.2L automatic transmission, 30,000 miles. DTC 0507 indicates an Idle Air Control (IAC) valve issue — the system detects higher-than-expected idle speed at 1200 RPM. DTC 0717 shows a missing signal from the Input/Turbine Speed Sensor, which prevents upshifting out of first gear and is directly related to transmission performance. I have thoroughly inspected all components in the air intake system — no visible leaks, damaged hoses, or loose wiring. However, I cannot locate the Input/Turbine Speed Sensor physically; it appears absent from standard sensor locations. Given that both codes are present, I am considering whether they are related. While DTC 0507 points to an IAC issue and DTC 0717 to a transmission sensor failure, I suspect one may be causing or exacerbating the other. What should I prioritize in troubleshooting? Any insights into common causes for these codes on this model? Is there a known wiring or sensor location issue specific to the 2004 Pontiac Sunfire?

Related fault codes
P0507P0717
Comments (6)
Anonymous 2009-05-14 22:02

Update: DTC 0717 was resolved by adding transmission fluid to the maximum capacity — likely addressed a low-pressure issue. The car now shifts properly, but DTC 0507 remains unresolved.

Anonymous 2009-05-15 07:29

Try spraying starting fluid onto all vacuum hoses and observe if idle changes. A vacuum leak could be causing the high idle. Also, move the wiring harness around to check for an open or broken wire — I’ve seen similar issues before where damaged wiring caused erratic idle behavior.

Anonymous 2009-05-15 11:47

Vacuum leaks typically don’t trigger DTC 0507. The more likely culprits are a faulty Throttle Position Sensor (TPS) or a sticking IAC motor. Also, check the throttle stop screw — if someone has adjusted it too tightly, it can artificially raise idle speed.

Anonymous 2009-05-15 11:57

The vehicle was a one-owner car with low mileage, so mechanical tampering is unlikely. However, I’ll double-check the throttle stop adjustment just in case. Thanks for the tip — could the TPS or IAC still throw a code if they’re faulty? I’m trying to rule out sensor issues.

Anonymous 2009-05-15 15:00

DTC 0507 means the Powertrain Control Module (PCM) cannot command the IAC valve to reduce idle speed. Even if the TPS circuit is technically functional, a high voltage reading (e.g., 0.65V instead of the expected 0.45V at idle) can cause the system to raise idle. This misreading leads the PCM to fail in controlling idle via IAC — suggesting either a faulty IAC valve or an incorrect sensor signal. The IAC should be tested before replacement, as it may not be fully defective but rather operating outside specifications.

Anonymous 2009-05-17 16:09

Thanks for all the input! Skydrol — are you familiar with transmission-related diagnostics (AV side)? Asecmt — what cleaner would you recommend for a sticking IAC valve? I have MAF cleaner on hand. Also, where can I find TPS voltage specifications? Are they available in online resources or only in dealer repair manuals like Haynes? Appreciate the help.