Free ASE A6 Exam Flashcards

V = I x R (Voltage = Current x Resistance). Rearranged as I = V/R or R = V/I, it underlies every electrical diagnostic calculation on the A6 test, from predicting current draw to explaining why added resistance drops voltage at a load.

Voltage drop only appears when current is flowing through a resistance. Testing an unpowered or unloaded circuit shows no drop even if a connection is badly corroded, so the circuit must be operating (lights on, motor running) during the test.

0.1V (100 mV). A reading above that on one connection points to corrosion or looseness there; total-circuit specs are higher and vary by circuit (for example, 0.2V is the accepted max across the starter's positive cable).

Roughly 20-50 mA. A reading in the hundreds of mA usually means a module failed to go to sleep, a relay is stuck, or an aftermarket accessory is staying powered - isolate it by pulling fuses one at a time (or using a current probe) after all modules time out.

An ohmmeter/continuity function sends its own small test current through the circuit. Applied battery voltage overwhelms that test current, produces false readings, and can damage the meter's internal circuitry.

When you need to see how a signal changes over time - CAN bus traffic, crank/cam sensor patterns, injector or coil firing, or fast glitches a DMM would average out and miss entirely.

Recessive (idle): CAN-H and CAN-L both sit near 2.5V, so the differential is about 0V. Dominant (active bit): CAN-H rises to about 3.5V and CAN-L drops to about 1.5V, creating a roughly 2V differential the receiving modules detect.

60 ohms. The two 120-ohm resistors sit in parallel, one at each end of the bus: (120 x 120)/(120+120) = 60 ohms. A reading far from 60 ohms across CAN-H/CAN-L points to a missing or damaged terminator.

LIN (Local Interconnect Network) is a single-wire, low-speed bus (about 19.2 Kbps) used for non-critical body functions like seat or mirror switches. High-speed CAN uses two wires (CAN-H/CAN-L) and runs far faster for powertrain and safety-critical communication.

It translates and routes messages between different bus protocols (such as CAN, LIN, and MOST) that run at different speeds or use different signaling, so modules on separate networks can still exchange data.

A fuse is a one-time sacrificial link sized to open at a specific overcurrent. A circuit breaker opens on overcurrent but can reset. A fusible link is a short section of smaller-gauge wire built into a harness to protect an entire circuit, and it must be replaced with an identical link - never system-sized wire - or the circuit loses its protection.

A splice point - the wires are electrically joined there. A crossing line with no dot means the wires simply pass over or under each other with no connection.

The module detected so many transmit errors that it disabled its own CAN transmitter to avoid corrupting bus traffic. It typically needs a key cycle or full communication reset once the underlying fault (wiring, termination, or module) is repaired.

About 12.6V. Roughly 12.4V equals about 75% charge, 12.2V equals about 50% charge, and 12.0V or below equals about 25% charge or less - each 0.2V step represents roughly 25% of state of charge.

AGM (Absorbent Glass Mat) holds its electrolyte absorbed in fiberglass mats instead of free liquid, making it sealed, spill-proof, and maintenance-free. It tolerates deeper cycling and faster charge acceptance, which is why it's required on most vehicles with stop-start systems.

Enhanced Flooded Battery - an upgraded flooded design built for entry-level stop-start systems. It offers better cycling and charge acceptance than a standard flooded battery but costs less than AGM.

Apply a load equal to half the battery's CCA rating for 15 seconds; voltage should stay above 9.6V at 70 degrees F. A battery that sags below that under load has a weak cell or insufficient reserve capacity even if its resting voltage looked fine.

It sends a small AC signal through the battery to measure internal resistance and current-delivery capability, catching a battery that reads acceptable open-circuit voltage but can no longer deliver cranking current - especially useful on AGM batteries.

Roughly 50-100 amps (6-cylinder about 75-150A, 8-cylinder about 100-200A). Draw well above these ranges points to a shorted/dragging starter or excessive engine mechanical resistance; draw well below can mean high resistance in the circuit.

0.2V (200 mV). Above that indicates corrosion, a loose terminal, or an undersized/damaged cable robbing the starter of cranking power even when the battery itself tests good.

Classic symptom of a battery too weak (or a connection with too much resistance) to hold the solenoid engaged - it pulls in, voltage sags, it drops out, and the cycle repeats. Confirm with a load test and a cranking voltage drop test before condemning the starter.

Blocks the starter control circuit unless the automatic transmission is in Park or Neutral, preventing the vehicle from cranking - and lurching - while in gear.

13.5-14.5V. Below 13.5V signals undercharging (weak alternator, slipping belt, excess load); above roughly 14.5-15V signals overcharging, usually a regulator that isn't limiting field current.

(1) The alternator isn't turning - a broken or slipping belt; (2) an open in the B+ output circuit; (3) an internal alternator fault (diodes, regulator, or field winding). The lamp is wired to light whenever the alternator isn't producing regulated output.

Measures leftover AC voltage riding on the DC output. Normal ripple is under about 100-200 mV; readings above roughly 500 mV point to one or more failed rectifier diodes letting AC pass through instead of being fully rectified.

A healthy alternator should still deliver close to its rated output - commonly cited as at least about 90% of rating near 2000 RPM under full load. Output that falls well short signals worn diodes, a bad stator, or a slipping belt/pulley.

The PCM/BCM commands alternator output based on battery temperature, state of charge, and electrical demand rather than a fixed set voltage - improving fuel economy by reducing alternator drag when full output isn't needed.

Classic sign of a failing or incorrect HID bulb. HID color and brightness change as the bulb ages, or a mismatched aftermarket bulb was installed; genuine failure usually needs bulb (and sometimes ballast) replacement, not just an aim adjustment.

LEDs draw far less current than the incandescent bulbs the flasher/module was calibrated for, so the current-sensing flasher reads it as a burned-out bulb and speeds up. Fix with load resistors wired in parallel with the LEDs or an LED-compatible flasher/module.

They drive the existing high-beam (or low-beam) headlight elements at reduced voltage or with Pulse Width Modulation (PWM), giving daytime visibility without full headlight intensity or a dedicated DRL circuit.

Primarily steering angle sensor input combined with vehicle speed; some systems add yaw rate to anticipate the vehicle's path through a curve before the wheel is even fully turned.

Suspect a shared cause first: a blown fuse feeding several circuits, a common ground failure, or a faulty lighting control module managing multiple outputs - before assuming several bulbs failed simultaneously by coincidence.

Trailer lighting/brake control runs through dedicated relays, connectors, and often a brake control module that mimics the trailer's electric brake signal; verify power, ground, and the control module's output signal separately from the tow vehicle's own brake light circuit.

Over a data bus (CAN/LIN) from modules like the PCM or BCM, rather than dedicated point-to-point wires from each sensor - so a cluster fault can trace back to a bus communication problem, not just the cluster itself.

A stepper motor gauge uses a small precision electric motor to position the needle in discrete steps commanded digitally, giving more accurate, repeatable movement than the analog air-core (crossed-coil) design it replaced.

Points to the fuel level sending unit or its wiring/ground - the sender outputs a variable resistance based on float position, and an open, short, or corroded ground in that circuit sends a false low (or high) signal to the cluster.

Because both directions are affected, suspect high resistance in the shared power/ground path (corroded connector, damaged wiring) or a mechanically binding window regulator - a single switch failure would typically affect only one direction.

Position sensors (potentiometers or Hall-effect) on each seat motor continuously report location to a memory/BCM module, which stores preset values and drives the motors back to them when a memory button or paired key fob is used.

Isolate to that door first: check power and ground at the actuator connector, then the actuator motor itself, before suspecting the body control module - a shared module fault would normally affect more than one door.

On resistor-block designs, low and medium speeds route through a series resistor; if only high (which bypasses the resistor) works, the blower motor resistor has failed. On PWM-controlled systems, suspect the blower control module instead.

Check the heating element/pad for continuity and correct resistance, verify the seat's thermostat/temperature sensor, and confirm power and ground at the seat module - an open heating element (a common wear/flex failure) reads infinite resistance.

Run a voltage drop test along the grid line with the defroster energized - voltage steps down evenly across a good line, but jumps sharply at the break location (near 0V past the break, or full battery voltage right up to it).

The key's transponder chip transmits a code to the immobilizer module; if that code doesn't match what's programmed (wrong key, failing chip, module fault), the immobilizer blocks starting - usually by disabling injectors or ignition rather than the starter itself.

Most often a weakening battery inside the fob reducing transmission range/reliability; also check for RF interference or a failing receiver module if a fresh battery doesn't fix it.

The security/theft-deterrent module has faulted or failed to disarm - check for a flashing security indicator (a stored fault code), verify the module is receiving its arm/disarm signal, and inspect wiring to the starter/fuel disable circuit it controls.

The SRS control module detected and stored a fault and has disabled airbag deployment until the fault is repaired and codes cleared - the vehicle can still be driven, but the airbags will not deploy in a crash.

A coiled ribbon connector in the steering column that keeps continuous electrical continuity to the driver airbag, horn, and steering wheel controls while still allowing full steering wheel rotation. A damaged clock spring can cause airbag faults, a dead horn, or non-functional wheel controls all at once.

Disconnect the negative battery cable and wait the manufacturer-specified time (commonly 1-3 minutes) before touching any SRS wiring or components - reserve capacitors in the SRS module can still fire an airbag even with the battery disconnected.

Check the wiper motor's park switch circuit first - it's what tells the motor to keep running until the blades reach the park position - along with the wiper control module/switch and the motor's power and ground.

Power and ground at the camera/sensor module, the video or data signal path to the display/BCM, and (for park-assist) the ultrasonic sensor's own self-test/communication with its control module - a 'no image' or 'system unavailable' message can originate from any point in that chain.