Powertrain Controls - ECM/PCM

1993 Geo Prizm L4-1600cc 1.6L DOHCSECTION Powertrain Controls - ECM/PCM

No Ignition Signal - Part 1 0f 2:




No Ignition Signal - Part 2 0f 2:




Ignition Circuit:






Circuit Description:
The engine control module (ECM) provides 5 volts to the igniter. The igniter in turn processes this voltage and returns it to the ECM as a signal (Ignition Fail-Safe Signal). The ECM also receives a 0.70 volt signal (Ignition Signal) when the starter is being cranked. The ECM uses these signals, along with others, to determine when to energize the fuel injectors.

DTC 14 will set if the following condition is met:

Ignition fail-safe signal is not received at the ECM for four consecutive ignition signals.


Test Description:
1. This checks for the 5 volts from the ECM.

2. Verifies the 0.10 - 2.0 volt signal from the ECM.

3. Checks to see if voltage is supplied to the distributor.

4. Checks for an open in BLK/ORN wire between junction block 1 and distributor or for a faulty junction block 1.

5. This checks for opens in the power feed to the igniter, for a faulty ignition coil and for a faulty igniter.

6. This checks for an open in the RED/BLK or BLK/ORN wire to the ignition switch and for a faulty ignition switch.


Diagnostic Aids:
An intermittent may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connections before component replacement.

RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.