By iCarsoft Official Store Technical Team, Automotive Diagnostics Editors · Updated September 21, 2026 · OEM technical references checked
Quick Answer
P0690 concerns ECM/PCM Power Relay Control Circuit High. The code does not prove the ECM or PCM is failed, the relay is stuck on, or high voltage at one point explains the whole circuit. Save the event, test battery and relay feeds, control and ground paths, and confirm the correct power-down behavior before replacing modules.
What Does the P0690 Code Mean?
The P0690 code means ECM/PCM Power Relay Control Circuit High. It names a monitored result, not a guaranteed failed part. The reporting module, suffix and companion faults determine the relevant test branch.
The ECM/PCM power relay circuit can include battery feed, ignition input, relay coil, relay contacts, keep-alive memory, grounds and controller drivers. P0690 names a high control-circuit result, not a complete power-distribution diagnosis.
A circuit-high code may be set by a stuck feed, open ground, backfeed, relay problem or controller driver branch. The test point and state matter.
The standardized description is ECM/PCM Power Relay Control Circuit High. Relay naming, module wake strategy and power-down timing vary by manufacturer and VIN.
Keep battery-voltage, ignition-state and relay-control evidence in the record. Do not replace a module until external power and ground paths are proven.
Read the stored wording exactly as the vehicle reports it. A short generic label can hide a manufacturer suffix, a circuit-direction detail, a bank or sensor identifier, or a setup condition that changes the first test. Save that wording before clearing the record so the diagnostic path can be repeated if the fault returns.
Separate P0690 from adjacent fault families
| Code | General description | Key distinction |
|---|---|---|
| P0690 | ECM/PCM Power Relay Control Circuit High | Use the full OEM wording, status and companion faults before choosing a test path. |
| P0685 | Code guide | Related monitor family; confirm its separate fault criteria before combining repairs. |
| P0686 | Code guide | Related monitor family; confirm its separate fault criteria before combining repairs. |
| P0687 | Code guide | Related monitor family; confirm its separate fault criteria before combining repairs. |
Record the complete P0690 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.
P0690 Symptoms and Likely Causes
P0690 symptoms depend on fault status and the fallback strategy. Record what the driver and modules reported. A symptom list is not a parts list.
Look for patterns rather than isolated clues. A current fault with matching freeze-frame data deserves a different priority than an old history fault found during unrelated service. Companion codes can point to a shared feed, ground, connector, fluid state, mechanical path or controller condition, but they still need the same evidence-based separation.
Save all module codes, voltage data and ignition-state records.
Record whether the fault appears after key-off, hot soak, low battery or jump starting.
Treat unsafe stalling as a stop-driving condition.
Measure the correct circuit state before replacing a relay.
Practical cause-checking order
- Power-distribution identity: Confirm the exact ECM/PCM power relay, fuse, battery feed, ignition input and control strategy for this VIN.
- Battery and relay evidence: Inspect battery condition, charging system evidence, fuse seats, relay pins, grounds and recent electrical work.
- Loaded circuit evidence: Test relay coil and contact circuits under the commanded state with voltage-drop and loaded-circuit methods.
- Backfeed or harness evidence: Check for backfeeds, open grounds, stuck relay contacts, short-to-voltage and harness damage before condemning the module driver.
- Controller or service action: Evaluate controller, programming or service-action branches only after external power distribution is proven.
Did P0690 appear after recent battery replacement, jump start, alternator service, fuse-box work, alarm or remote-start wiring, water intrusion or module service? 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 P0690, and Can You Drive?
P0690 alone cannot establish a safe driving distance. If operation is normal, follow the owner's manual and arrange prompt diagnosis. Stop for stalling, unreliable starting, unexpected warning-lamp cycling, electrical odor, or abnormal module power-on behavior.
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. If the vehicle enters a reduced-power strategy, develops abnormal noise, leaks fluid, overheats or shows a red stop warning, the safety condition overrides any plan to complete a drive cycle.
Stop and arrange a tow if the engine stalls, the vehicle will not start reliably, warning lamps cycle unexpectedly, electrical burning smell appears, or module power stays on abnormally.
Use OEM electrical precautions. Do not short relay terminals, power a module with unidentified jumpers or disconnect battery power before saving volatile diagnostic information unless safety requires it.
How to Diagnose P0690 in the Right Order
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Save the P0690 power event
Save all powertrain and network codes, freeze frame, system voltage, ignition state and recent low-voltage or jump-start history before clearing anything.
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Map the relay and power feeds
Use the VIN wiring diagram to identify the ECM/PCM power relay, fuses, coil control, contact feed, grounds and expected power-down sequence.
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Inspect battery, fuses and grounds
Inspect battery state, charging evidence, fuse and relay seating, ground points, corrosion, water intrusion and aftermarket wiring.
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Test relay command and voltage drop
Measure supply, ground, relay coil and contact voltage drop in the commanded states. A no-load voltage reading alone can miss resistance or backfeed faults.
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Check for backfeed or stuck power
Check for short-to-voltage, stuck relay contacts, open control ground or another circuit feeding the relay when it should be off.
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Repair and verify key-off behavior
Repair the proven relay, terminal, feed, ground, harness or controller branch. Verify start, run and key-off behavior plus pending-code status.
Specifications are vehicle-specific. Use the exact VIN specifications, approved test points and required operating state. No generic value or drive cycle can replace the applicable procedure. Manufacturer examples here do not establish specifications for other applications.
P0690 Repairs and Typical Costs
The correct P0690 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.
Recheck installation and required setup after repair. Low battery, jump-start events and recent electrical work can create misleading power-relay evidence; record them before clearing codes.
A useful estimate should name the failed branch, not just the code. Ask whether the shop found an open, short, biased signal, missing supply, poor ground, mechanical restriction, fluid condition, calibration requirement or module fault. That wording makes the recommendation auditable and protects against replacing several unrelated parts after one stored DTC.
When the failed branch is still uncertain, pay for diagnosis before authorizing parts. A careful proof step is usually less disruptive than repeating repairs after the same monitor sets again.
| Possible path | Current US estimate |
|---|---|
| Restore a proven battery feed, fuse, relay terminal, ground or harness fault | VIN-specific quote |
| Replace the relay only when contact or coil tests support it | VIN-specific quote |
| Remove or correct backfeed sources from water damage or aftermarket wiring when proven | VIN-specific quote |
| Consider ECM/PCM driver, programming or replacement only after external circuits pass the OEM tests | VIN-specific quote |
These are alternative repair paths, not prices to add together. Request a VIN-specific quote separating diagnosis, parts, labor, fluids, taxes, required setup and verification. Ask which failed test supports the proposed repair and whether warranty coverage applies.
Using iCarsoft CR Max P for P0690
On a supported vehicle, iCarsoft CR Max P can retrieve accessible module faults, save available freeze frame, display ECU-provided live data and create a diagnostic report. For P0690, preserve the original evidence and compare related modules before clearing an erasable record.
Use the report as a record of what the controller knew at the time. It helps compare code status, freeze-frame conditions and available PIDs before and after repair. It does not replace the wiring diagram, service procedure, safe access instructions or physical measurement required to prove the failed branch.
Preserve the ECM/PCM power relay control circuit high condition evidence
iCarsoft CR Max 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 P0690-specific function.
Check current CR Max P price and availabilityCheck CR Max P compatibility by VINThe official product page describes supported vehicle diagnostics, available service functions, live data and reports; exact module access and functions depend on 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. Scan data describes ECU-provided information; it does not directly prove the physical condition of the ECM/PCM power relay control circuit high condition. Use a scan tool, high-impedance meter, voltage-drop and loaded-circuit tools, relay test information and OEM wiring diagrams where required, and compare reported values with the relevant measured evidence.
Verify the P0690 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 ECM/PCM power relay control circuit high condition, and check current and pending faults in related modules. One clean start or idle period does not prove that every conditional monitor has completed.
Document what changed between the first scan and the verification scan. Useful notes include module status, current versus history state, freeze-frame differences, whether the same enabling conditions returned, and whether a relearn or service function was accepted. Preserve the original diagnostic fault order. This record helps separate an incomplete monitor from a repair that failed under the same conditions.
If P0690 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 P0690 can remain immediately after a successful repair. If stored as a permanent DTC, it cannot be erased by a scan tool or battery disconnect. The vehicle must complete the applicable successful monitor verification.
Related ECM/PCM Power Relay Control Circuit High Condition Code Guides
Use related-code pages to compare monitor families, not to merge repairs. A nearby code can share a component, circuit, fluid path or operating condition, but its diagnostic conclusion still depends on its own status, suffix and test evidence.
P0690 Frequently Asked Questions
Does P0690 mean the ECM or PCM must be replaced?
No. P0690 describes a high condition in the ECM/PCM power relay control circuit. Battery, relay, feed, ground, backfeed and wiring evidence must be checked before any module decision.
What should I check first for P0690?
Save every module's codes and freeze frame before clearing. Confirm the full definition, suffix and VIN architecture. Then inspect recent battery replacement, jump start, alternator service, fuse-box work, alarm or remote-start wiring, water intrusion or module service, connectors and shared supplies. Those facts determine whether the next test needs a scan tool, high-impedance meter, voltage-drop and loaded-circuit tools, relay test information and OEM wiring diagrams or a manufacturer-specific functional procedure.
Can I drive with the P0690 code?
P0690 alone cannot establish a safe driving distance. If operation is normal, follow the owner's manual and arrange prompt diagnosis. Stop for stalling, unreliable starting, unexpected warning-lamp cycling, electrical odor, or abnormal module power-on behavior.
Why did P0690 return after a part was replaced?
Module replacement is a last branch because programming, theft, immobilizer and network setup can be required.
What should a P0690 repair estimate include?
Ask for the failed-test evidence and a VIN-specific breakdown of diagnosis, parts, labor, taxes, required setup and verification. A code alone cannot establish the repair price.
Can CR Max P diagnose and clear P0690?
On a supported vehicle, CR Max 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 ECM/PCM power relay control circuit high condition.
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
- SAE J2012 DTC terminology. The control-circuit-high wording does not prove a module failure or universal relay test point.
- California Bureau of Automotive Repair — OBD test reference. Use monitor and readiness evidence after repair rather than treating a cleared code as proof.
- 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 Max 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.
