The Throttle Position Sensor (TPS) tells the ECU how far the throttle is open. If it's incorrectly adjusted, the ECU may receive inaccurate throttle-position information, resulting in poor drivability, hesitation, idle issues, or inconsistent throttle response.
This is especially important on modified Honda and Acura engines running a chipped OBD1 ECU.
Fortunately, checking and calibrating the TPS is fairly simple with a digital multimeter.
Correct Honda TPS Voltage
For DGTune OBD1 applications, we recommend the following TPS voltage targets:
| Throttle Position | Target Voltage |
|---|---|
| Fully Closed | 0.47V |
| Wide Open (WOT) | 4.55V |
These are recommended targets. Small variations around these values are generally acceptable, provided the sensor operates correctly and the ECU recognizes both closed and wide-open throttle.
The voltage should increase smoothly as the throttle opens, without sudden jumps or dropouts.
What You'll Need
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Digital multimeter capable of reading DC voltage
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Small screwdriver or appropriate TPS mounting tools
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Back-probe pins or suitable electrical test probes
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Access to the throttle body and TPS connector
Step 1: Locate the TPS
The TPS is mounted on the side of the throttle body, opposite the throttle cable linkage.
Most Honda and Acura TPS sensors use a 3-wire connector:
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5V reference — supplied by the ECU
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Sensor ground — ground reference from the ECU
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TPS signal — varying voltage sent back to the ECU
The TPS signal wire is commonly the center terminal on older Honda applications, but verify the wiring for your specific vehicle before testing.
Step 2: Connect Your Multimeter
Leave the TPS connector plugged in.
Turn the ignition key to the ON position without starting the engine.
Set your multimeter to DC voltage.
Connect:
Red multimeter probe → TPS signal wire
Black multimeter probe → TPS sensor ground
Use back-probing to measure the signal without disconnecting the sensor.
Be careful not to short adjacent terminals while testing.
Step 3: Check Closed-Throttle Voltage
With the throttle completely closed and your foot off the accelerator, check the voltage.
Target: 0.47V
If the reading is significantly higher or lower, the TPS may need adjustment.
Before adjusting anything, make sure the throttle cable isn't too tight and the throttle plate is returning completely to its normal closed position.
Do not use the throttle stop screw to adjust TPS voltage.
Step 4: Adjust the TPS
If your TPS is adjustable, slightly loosen its two mounting screws.
Rotate the TPS carefully while watching the multimeter.
Adjust it until the signal reads approximately:
0.47V with the throttle fully closed.
Once the correct voltage is reached, tighten the mounting screws without allowing the sensor to move.
Some factory Honda TPS sensors use tamper-resistant mounting screws or rivets instead of normal screws. These may need to be replaced with suitable screws if the sensor requires adjustment or replacement.
Step 5: Verify Wide-Open Throttle Voltage
Now manually open the throttle completely.
Make sure the throttle plate reaches its fully open position.
Target: 4.55V
The voltage should be approximately 4.5–4.6V when the throttle is fully open.
Remember, you're adjusting the TPS primarily at closed throttle. The fully open reading is used to verify that the sensor and throttle mechanism are operating correctly.
If the closed-throttle voltage is correct but the wide-open reading is significantly incorrect, check the sensor, 5V reference, ground, throttle movement, and wiring.
Do not deliberately misadjust the closed-throttle voltage just to force an exact 4.55V reading.
Step 6: Check the Entire Throttle Range
Slowly open the throttle from fully closed to fully open while watching the multimeter.
The voltage should increase smoothly from approximately 0.47V to 4.55V.
Then slowly close the throttle and watch the voltage decrease.
There should be no sudden voltage jumps, dropouts, or dead spots.
If the reading suddenly drops, spikes, or becomes inconsistent, the TPS may be worn or damaged.
A faulty TPS cannot be fixed simply by adjusting its position.
What Happens If the TPS Is Incorrectly Calibrated?
An incorrectly adjusted or malfunctioning TPS can cause:
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Hesitation when accelerating
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Poor throttle response
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Incorrect acceleration enrichment
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Unstable idle or poor idle recovery
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RPM hanging during deceleration
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Inconsistent fuel delivery during throttle changes
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Problems with throttle-dependent tuning features
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Check Engine Light Code 7 on applicable OBD1 ECUs
The ECU relies on accurate TPS information to determine driver throttle input.
If the TPS reports an incorrect position, the calibration may respond differently than intended.
Important for Chipped ECU and Remote Tuning Customers
If you're running a DGTune custom chip tune, Hondata S300, or Snake Emulator, TPS calibration should be verified before requesting tuning adjustments.
For example, if the TPS incorrectly reports that the throttle is partially open when it's actually closed, the ECU may not operate its normal idle and deceleration functions correctly.
Similarly, an inaccurate wide-open-throttle reading can affect tuning functions that depend on TPS position.
We recommend verifying approximately 0.47V closed and 4.55V fully open before attempting to diagnose throttle-related tuning issues.
Quick TPS Calibration Checklist
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Turn ignition ON, engine OFF.
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Leave the TPS connected.
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Back-probe the TPS signal and sensor ground.
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Verify approximately 0.47V at closed throttle.
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Adjust the TPS if necessary.
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Open the throttle fully and verify approximately 4.55V.
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Slowly sweep the throttle open and closed to check for smooth voltage changes.
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Tighten the TPS mounting screws and recheck both readings.
If both voltage readings are correct and the signal changes smoothly throughout the throttle range, your TPS should be properly calibrated.
Need Help With Your Honda ECU Tune?
Before requesting a tuning adjustment, make sure your TPS, ignition timing, fuel pressure, mechanical timing, and other engine sensors are functioning correctly.
A custom calibration can only perform as intended when the ECU receives accurate information from the engine.
DGTune specializes in Honda and Acura OBD1 ECU tuning, chipped ECUs, ECU socketing, and remote tuning.