By iCarsoft Official Store Technical Team, Automotive Diagnostics Editors · Updated September 8, 2026 · OEM technical references checked
Quick Answer
The P1681 code needs the exact manufacturer definition before parts testing. Record the VIN, storing module and full OEM text. Documented GM examples concern a control-module throttle-position diagnostic, but that meaning must not be assigned to another application. A code number alone does not establish a failed PCM or throttle body.
What Does the P1681 Code Mean?
P1681 is manufacturer controlled, so its meaning must come from the exact vehicle and storing module. The GM throttle-position examples below are one documented branch, not a cross-brand definition. It names a monitored result, not a guaranteed failed part. The reporting module, suffix and companion faults determine the relevant test branch.
P1xxx is manufacturer controlled. Use exact make/model/engine/module text first. The researched GM examples monitor the controller's throttle-position sensor-short diagnostic; they do not define every manufacturer's P1681.
A monitor differs from the component it supervises. The cited GM examples include checking a throttle-position diagnostic. A plausible position value cannot independently prove that this internal checking process passed.
GM's 2004 2.8L LK5/3.5L L52 diagnostic table names Control Module Throttle Position System Performance. The 2003 4.2L LL8 table separately describes a TPS performance check. Both concern the ability to detect/control a throttle sensor short-test state.
GM’s tables cover specified engines and establish no cross-brand meaning. Their internal short-test states do not authorize manually shorting sensor wiring.
Separate P1681 from adjacent fault families
| Code | General description | Key distinction |
|---|---|---|
| P1681 | Manufacturer-controlled; exact OEM meaning required | The researched GM branch is an example, not a universal interpretation. |
| B1681 | A different body-code identifier | The changed letter is significant; do not import its meaning or test procedure into P1681. |
| P0122 | Throttle/pedal position sensor or switch A circuit low | A distinct sensor-circuit classification; it does not define the controller diagnostic in every P1681 application. |
| P0123 | Throttle/pedal position sensor or switch A circuit high | The high-direction circuit code remains separate from P1681 and requires its own application-specific checks. |
Record the complete P1681 description. The suffix, reporting module and companion faults can change the diagnostic path. Use the manufacturer's full wording and test procedure for the exact vehicle.
P1681 Symptoms and Likely Causes
P1681 symptoms depend on fault status and the fallback strategy. Record what the driver and modules reported. A symptom list is not a parts list.
Save the full description exactly as reported, including the storing module. Different wording is a reason to verify identity before selecting a system or buying a part.
On a matching documented application, record throttle response and associated faults. Reduced power alone does not prove that the internal monitor, sensor or throttle assembly is defective.
Describe the actual symptom independently of the internet code label. Unsafe operation determines the immediate response even when the manufacturer-specific meaning has not yet been resolved.
Record hardware, software and battery history. A post-repair occurrence requires checking identity and required setup, but does not automatically authorize another controller or a programming attempt.
Practical cause-checking order
- Identity before diagnosis: An incorrect cross-brand definition can send diagnosis toward the wrong system. This is a diagnostic error rather than a physical cause of the stored fault; resolve it before choosing any component test.
- GM electrical path: For the documented GM branch, verify controller supplies, grounds and throttle-sensor wiring. Test suspected connector or shared electrical defects against the applicable diagram.
- Supporting evidence: Companion throttle-position, supply or controller faults may change the prescribed test order on a matching GM application. Preserve the complete combination instead of assuming that a single position reading proves the diagnostic system works.
- GM diagnostic-state branch: The cited GM monitor concerns throttle-position diagnostic capability. Separate wiring, connected-sensor behavior and the internal diagnostic; this code alone does not identify the failed part.
- Configuration branch: Investigate incorrect hardware, software or incomplete setup when the OEM procedure supports that branch. Confirm prerequisites before programming; flashing cannot replace unresolved electrical tests.
Did P1681 appear after recent controller or software work relevant to the OEM definition? Recheck the documented connections, parts and setup steps affected by that work. Record battery and software history; a post-repair code does not prove the new part is defective.
How Serious Is P1681, and Can You Drive?
Assess the actual warning and symptoms before moving. A generic P1681 lookup cannot establish safe operation; arrange professional diagnosis.
Record temperature, load, speed, start state and recent service. Do not reproduce a severe symptom on public roads; another warning can make the situation more urgent.
Stop and arrange a tow if unintended acceleration, erratic throttle, repeated stalling, unsafe reduced power or critical instrument loss develops.
Keep hands and tools clear of a powered electronic throttle. Do not create a sensor short with jumpers to imitate a controller’s internal diagnostic. If the manufacturer definition is unresolved, stop component testing until the correct procedure is available.
How to Diagnose P1681 in the Right Order
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Save the exact code, module and OEM text
Save the raw code with its P prefix, storing module, manufacturer text and available failure record. Record vehicle identity and the actual warning or symptom. Do not replace that evidence with a search-result description, and do not treat B1681 as another spelling of the same fault.
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Resolve the manufacturer-specific definition first
Match VIN, model year, engine and controller identification to current OEM service information. Confirm the full definition and its diagnostic prerequisites. If the wording remains uncertain, stop here and obtain the correct information; no generic throttle, communication or fuel-system test should be substituted for an unresolved manufacturer-controlled code.
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Select only the confirmed system branch
Follow the system identified by the OEM procedure. On the cited GM applications, review the throttle-position and controller diagnostic context plus companion faults. Do not expand that route to another make merely because P1681 matches, and do not use a clean throttle body as proof that an internal diagnostic passed.
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Test the specified supplies and signal paths
Inspect and test only the documented controller supplies, grounds, terminals and relevant sensor wiring. Use the required isolation state and instruments. Do not deliberately short position-sensor circuits to mimic a monitor self-test, and do not interpret a generic resistance reading as approval to replace the controller.
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Follow the actual controller or programming decision
Have qualified service complete the prescribed internal diagnostic and evaluate any hardware or programming decision against its prerequisites. Check replacement and software history without presuming that an update is the remedy. A module should not be condemned merely because the code description contains the words control module.
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Verify the manufacturer-specific monitor safely
Repair the evidenced branch and complete the required configuration or learning steps. Verify the actual manufacturer-specific monitor, associated data and safe vehicle operation. Save post-repair findings and returning fault text; successful code clearing cannot substitute for proof that the correct monitor ran and the original complaint was resolved.
Specifications are vehicle-specific. There is no universal voltage, resistance, current, pressure, waveform, timing, temperature, percentage, learned value or drive cycle for P1681. Test state, connector location and system design change what a valid value means. Use only specifications for the exact VIN and do not transfer the OEM example in this article to another application.
P1681 Repairs and Typical Costs
The correct P1681 repair follows the failed test. Wiring, a physical repair, a proven component, software and controller work are different outcomes. Do not replace an assembly from the generic code alone.
After installation, recheck connector seating, harness clearance, fluid or mechanical setup and every required learn. Attach controller repair or programming to the exact VIN, hardware and failed OEM test. Preserve identifiers; a software operation or warning reset does not establish successful monitor completion.
| Possible path | Current US estimate |
|---|---|
| Correct a proven electrical defect in the confirmed manufacturer-specific circuit | VIN-specific quote |
| Repair a component only after the applicable OEM diagnostic supports failure | VIN-specific quote |
| Apply verified hardware or software corrections with all prerequisites met | VIN-specific quote |
| Complete required module setup and verify the exact OEM monitor | VIN-specific quote |
There is no single national P1681 repair price because these rows are alternative outcomes. Ask for an itemized estimate showing diagnostic time, parts, labor, fluids, service-information access and verification. Location, taxes, related damage and warranty eligibility change the total. Do not add the rows together or authorize an assembly without the supporting failed test.
Using iCarsoft CR Eagle P for P1681
On a supported vehicle, iCarsoft CR Eagle P can retrieve accessible module faults, save available freeze frame, display ECU-provided live data and create a diagnostic report. For P1681, preserve the original evidence and compare related modules before clearing an erasable record.
Preserve the manufacturer-specific control diagnostic evidence
iCarsoft CR Eagle P
Review supported codes and relevant live data together. Confirm the exact VIN, controller access, PIDs and any requested active test with iCarsoft before purchase; generic product capabilities do not guarantee a P1681-specific function.
Check current CR Eagle P price and availabilityCheck CR Eagle P compatibility by VINThe official product page describes full-system diagnostics, available freeze frame and live data, and supported bidirectional tests and ECU coding; availability varies with the vehicle, ECU and software. Confirm the requested function by VIN before purchase. Follow OEM prerequisites and stop for abnormal operation.
Know the measurement boundary. The scanner reports information supplied by the vehicle. It does not directly prove terminal tension, circuit load capacity, leakage, pressure, temperature, mechanical travel or internal condition in the manufacturer-specific control diagnostic. It also cannot replace OEM-specified electrical test equipment when the OEM procedure requires them. Interpret commanded and reported values alongside measured evidence.
Verify the P1681 Repair
After repair, verify connectors, harness clearance, setup and controller supply. Save post-repair findings, then clear only erasable records through the approved procedure. Battery disconnection is not a repair.
Run the manufacturer's applicable verification conditions in a safe workshop or route. Compare the original operating state with current data for the manufacturer-specific control diagnostic, and check current and pending faults in related modules. One clean start or idle period does not prove that every conditional monitor has completed.
If P1681 returns, compare its suffix, status, failure order and operating conditions with the saved baseline before replacing another part. Revisit the failed branch and inspect anything disturbed. Keep mechanical repair, monitor completion, readiness and local inspection eligibility as separate outcomes.
A permanent P1681 can remain immediately after a successful repair. If the vehicle stores it as a permanent DTC, a scan tool or battery disconnect cannot erase it. Once current and pending faults are absent, the OBD system removes the permanent record only after the applicable monitor reruns and passes.
Related Manufacturer-Specific Control Diagnostic Code Guides
P1681 Frequently Asked Questions
Does P1681 always mean a bad PCM or throttle body?
No. P1681 is manufacturer controlled. First identify the exact OEM definition and storing module. The documented GM examples concern a throttle-position diagnostic, but neither that example nor the code alone proves a failed controller or throttle body on another vehicle.
What should I check first for P1681?
Save every module's codes and freeze frame before clearing. Confirm the full definition, suffix and VIN architecture. Then inspect recent controller or software work relevant to the OEM definition, connectors and shared supplies. Those facts determine whether the next test needs OEM-specified electrical test equipment or a manufacturer-specific functional procedure.
Can I drive with the P1681 code?
Assess the actual warning and symptoms before moving. A generic P1681 lookup cannot establish safe operation; arrange professional diagnosis.
Why did P1681 return after a part was replaced?
If P1681 returns, reconfirm its prefix, module and full description. Incorrect interpretation, electrical faults or incomplete setup can survive replacement. Recheck the actual OEM monitor instead of repeating a generic reset.
What should a P1681 repair estimate include?
A VIN-specific estimate is required because diagnosis may lead to wiring, a supporting physical repair, a verified component, software or a controller. Ask which failed test supports the quote and whether diagnosis, taxes, setup and post-repair verification are included.
Can CR Eagle P diagnose and clear P1681?
On a supported vehicle, CR Eagle P can organize available faults, freeze frame, live data and reports, and can clear erasable records after repair. Confirm exact ECU coverage. It cannot force-clear a permanent DTC or replace physical measurements for the manufacturer-specific control diagnostic.
The iCarsoft Official Store Technical Team maintains the store's fault-code library. This guide organizes published manufacturer evidence and verified product information; it does not document a hands-on test of a particular vehicle or claim an individual engineer's review.
Technical and cost references
- GM 2004 2.8L LK5 / 3.5L L52 Engine Diagnostic Parameters. Specific P1681 Control Module Throttle Position System Performance monitor; not a cross-brand definition.
- GM 2003 4-cylinder and inline 6-cylinder Engine Diagnostic Parameters. P1681 TPS performance check scoped to 4.2L applications per table footnote.
- California Bureau of Automotive Repair — On-Board Diagnostic Test Reference. Permanent DTCs are removed by the vehicle after applicable verification, not by a scan-tool erase command.
Product information: Official iCarsoft CR Eagle P page.
Editorial note: General diagnostic education, not a substitute for the owner's manual, current VIN-specific service information or professional inspection. Test limits, procedures, coverage and costs vary. Related articles provide context; apply only the specifications and repair procedures that match the vehicle. No universal failure rate, repair price or outcome is implied.
